Apparatus and method for adjusting both a cyclic prefix length and a symbol interval of a complex symbol sequence

ABSTRACT

[Object] To adaptively adjust a symbol interval in accordance with a communication environment.[Solution] An apparatus including: a communication unit configured to perform radio communication; and a control unit configured to perform control such that control information for adjusting a symbol interval in a complex symbol sequence into which a bit sequence is converted is transmitted from the communication unit to a terminal, the control information being set on a basis of a predetermined condition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/758,910, filed Mar. 9, 2018, which is a National Stage Applicationbased on PCT/JP2016/070510, filed on Jul. 11, 2016, and claims priorityto Japanese Patent Application No. 2015-183902, filed on Sep. 17, 2015,the entire contents of each are incorporated herein by its reference.

TECHNICAL FIELD

The present disclosure relates to an apparatus and a method.

BACKGROUND ART

In the conventional modulation schemes applied in standards such as LTE(Long Term Evolution)/LTE-A (Advanced), the symbol intervals of symbolsmodulated in accordance with PSK/QAM or the like are set in accordancewith the Nyquist criterion such that temporally continuous symbols donot interfere with each other (i.e., no inter-symbol interferenceoccurs). This allows a reception apparatus side to demodulate and decodereception signals with no special signal processing but attendantprocessing such as orthogonal frequency-division multiplexing (OFDM) ormultiple-input and multiple-output (MIMO). However, from the perspectiveof frequency use efficiency, it is difficult to narrow the symbolintervals of the modulated symbols beyond conditions of the symbolintervals, so that the upper limit is defined in accordance with thegiven frequency bandwidth, the number of MIMO antennas, and the like. Itis considered to extend the frequency band of the communication systemfrom the existing microwave band to the submillimeter-wave band, themillimeter-wave band, or the like, which is higher frequency. However,the limit will be reached some day because of limited frequency bandresources. In addition, MIMO also has a physical restriction as to theinstallation of antennas in an apparatus, so that this will also reachthe limit.

Under such circumstances, the technology referred to asfaster-than-Nyquist (FTN) has attracted attention. For example, PatentLiterature 1 discloses FTN. FTN is a modulation scheme and atransmission scheme which narrow the symbol intervals of modulatedsymbols beyond the above-described conditions of the symbol intervals toattempt to improve frequency use efficiency. Although inter-symbolinterference occurs between temporally continuous symbols in the processof modulation, and a reception apparatus side requires special signalprocessing to receive FTN signals, such a configuration makes itpossible to improve frequency use efficiency in accordance with the wayto narrow symbol intervals.

CITATION LIST Patent Literature

Patent Literature 1: US 2006/0013332A

DISCLOSURE OF INVENTION Technical Problem

Meanwhile, in the case where FTN is applied, as described above,inter-symbol interference occurs between temporally continuous symbols.Accordingly, signal processing is necessary to allow a receptionapparatus side to receive FTN signals, and the signal processing can bea factor that increases the load on the reception apparatus side.

Accordingly, the present disclosure proposes an apparatus and a methodthat are capable of adaptively adjusting a symbol interval in accordancewith a communication environment.

Solution to Problem

According to the present disclosure, there is provided an apparatusincluding: a communication unit configured to perform radiocommunication; and a control unit configured to perform control suchthat control information for adjusting a symbol interval in a complexsymbol sequence into which a bit sequence is converted is transmittedfrom the communication unit to a terminal, the control information beingset on a basis of a predetermined condition.

In addition, according to the present disclosure, there is provided anapparatus including: a communication unit configured to perform radiocommunication; and an acquisition unit configured to acquire controlinformation for adjusting a symbol interval in a complex symbol sequenceinto which a bit sequence is converted from a base station via the radiocommunication, the control information being set on a basis of apredetermined condition.

In addition, according to the present disclosure, there is provided anapparatus including: a conversion unit configured to convert a bitsequence into a complex symbol sequence; an acquisition unit configuredto acquire control information for adjusting a symbol interval in thecomplex symbol sequence, the control information being set on a basis ofa predetermined condition; and a filtering processing unit configured toperform filtering processing on the complex symbol sequence, thefiltering processing being based on the control information.

In addition, according to the present disclosure, there is provided amethod including: performing radio communication; and performing, by aprocessor, control such that control information for adjusting a symbolinterval in a complex symbol sequence into which a bit sequence isconverted is transmitted to a terminal, the control information beingset on a basis of a predetermined condition.

In addition, according to the present disclosure, there is provided amethod including: performing radio communication; and acquiring, by aprocessor, control information for adjusting a symbol interval in acomplex symbol coefficient into which a bit sequence is converted from abase station via the radio communication, the control information beingset on a basis of a predetermined condition.

In addition, according to the present disclosure, there is provided amethod including, by a processor: converting a bit sequence into acomplex symbol sequence; acquiring control information for adjusting asymbol interval in the complex symbol sequence, the control informationbeing set on a basis of a predetermined condition; and performingfiltering processing on the complex symbol sequence, the filteringprocessing being based on the control information.

Advantageous Effects of Invention

As described above, according to the present disclosure, there areprovided an apparatus and a method that are capable of adaptivelyadjusting a symbol interval in accordance with a communicationenvironment.

Note that the effects described above are not necessarily limitative.With or in the place of the above effects, there may be achieved any oneof the effects described in this specification or other effects that maybe grasped from this specification.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory diagram for describing an example oftransmission processing in a case where FTN is employed.

FIG. 2 is an explanatory diagram for describing an example of receptionprocessing in the case where FTN is employed.

FIG. 3 is an explanatory diagram illustrating an example of a schematicconfiguration of a system according to an embodiment of the presentdisclosure.

FIG. 4 is a block diagram illustrating an example of a configuration ofa base station according to the embodiment.

FIG. 5 is a block diagram illustrating an example of a configuration ofa terminal apparatus according to the embodiment.

FIG. 6 is an explanatory diagram for describing an example of aconfiguration of a time resource in a case where FTN is supported.

FIG. 7 is an explanatory diagram for describing an example of processingin a transmission apparatus that supports FTN.

FIG. 8 is an explanatory diagram for describing an example of theprocessing in the transmission apparatus that supports FTN.

FIG. 9 is an explanatory diagram for describing an example of theprocessing in the transmission apparatus that supports FTN.

FIG. 10 is an explanatory diagram for describing an example of theprocessing in the transmission apparatus that supports FTN.

FIG. 11 is a diagram illustrating an example of a relationship betweenfrequency of a channel, a level of inter-symbol interference, and acompression coefficient.

FIG. 12 is a flowchart illustrating an example of processing of settinga compression coefficient in accordance with frequency of a channel.

FIG. 13 is a diagram illustrating another example of the relationshipbetween frequency of a channel, a level of inter-symbol interference,and a compression coefficient.

FIG. 14 is a flowchart illustrating an example of processing of settinga compression coefficient in accordance with whether a target CC is aPCC or an SCC.

FIG. 15 is an explanatory diagram for describing an example of acommunication sequence in a case where FTN is employed for a downlink.

FIG. 16 is an explanatory diagram for describing an example of acommunication sequence in the case where FTN is employed for thedownlink.

FIG. 17 is an explanatory diagram for describing an example of acommunication sequence in a case where FTN is employed for an uplink.

FIG. 18 is an explanatory diagram for describing an example of acommunication sequence in the case where FTN is employed for the uplink.

FIG. 19 is a diagram illustrating an example of a frequency channel usedfor communication between a base station and a terminal apparatus in acommunication system in which carrier aggregation is employed.

FIG. 20 is an explanatory diagram for describing an example of acommunication sequence in a case where FTN is employed for a downlink ina communication system in which carrier aggregation is employed.

FIG. 21 is an explanatory diagram for describing an example of acommunication sequence in the case where FTN is employed for thedownlink in the communication system in which carrier aggregation isemployed.

FIG. 22 is an explanatory diagram for describing an example of acommunication sequence in the case where FTN is employed for thedownlink in the communication system in which carrier aggregation isemployed.

FIG. 23 is an explanatory diagram for describing an example of acommunication sequence in the case where FTN is employed for thedownlink in the communication system in which carrier aggregation isemployed.

FIG. 24 is an explanatory diagram for describing an example of acommunication sequence in the case where FTN is employed for thedownlink in the communication system in which carrier aggregation isemployed.

FIG. 25 is an explanatory diagram for describing an example of acommunication sequence in the case where FTN is employed for thedownlink in the communication system in which carrier aggregation isemployed.

FIG. 26 is a block diagram illustrating a first example of a schematicconfiguration of an eNB.

FIG. 27 is a block diagram illustrating a second example of theschematic configuration of the eNB.

FIG. 28 is a block diagram illustrating an example of a schematicconfiguration of a smartphone.

FIG. 29 is a block diagram illustrating an example of a schematicconfiguration of a car navigation apparatus.

MODE(S) FOR CARRYING OUT THE INVENTION

Hereinafter, (a) preferred embodiment(s) of the present disclosure willbe described in detail with reference to the appended drawings. Notethat, in this specification and the appended drawings, structuralelements that have substantially the same function and structure aredenoted with the same reference numerals, and repeated explanation ofthese structural elements is omitted.

Note that the description will be made in the following order.

1. FTN 2. Technical Problem 3. Schematic Configuration of System 4.Configuration of Each Apparatus 4.1. Configuration of Base Station 4.2.Configuration of Terminal Apparatus 5. Technical Features 6.Modifications 6.1. Modification 1: Example of Control of Prefix

6.2. Modification 2: Example of Control according to Moving Speed ofApparatus

7. Application Examples

7.1. Application Example regarding Base Station7.2. Application Example regarding Terminal Apparatus

8. Conclusion 1. FTN

First, with reference to FIGS. 1 and 2, the overview of FTN will bedescribed. In the conventional modulation schemes applied in standardssuch as LTE/LTE-A, the symbol intervals of symbols modulated inaccordance with PSK/QAM or the like are set in accordance with theNyquist criterion such that temporally continuous symbols do notinterfere with each other (i.e., no inter-symbol interference occurs).This allows a reception apparatus side to demodulate and decodereception signals without performing special signal processing (exceptfor attendant processing such as OFDM or MIMO. However, from theperspective of frequency use efficiency, it is difficult to narrow thesymbol intervals of the modulated symbols beyond conditions of thesymbol intervals, so that the upper limit is defined in accordance withthe given frequency bandwidth, the number of MIMO antennas, and thelike. It is considered to extend the frequency band of the communicationsystem from the existing microwave band to the submillimeter-wave band,the millimeter-wave band, or the like, which is higher frequency.However, the limit will be reached some day because of limited frequencyband resources. In addition, MIMO also has a physical restriction as tothe installation of antennas in an apparatus, so that this will alsoreach the limit.

Under such circumstances, the technology referred to asfaster-than-Nyquist (FTN) has attracted attention. FTN is a modulationscheme/transmission scheme which narrows the symbol intervals ofmodulated symbols beyond the above-described conditions of the symbolintervals to attempt to improve frequency use efficiency. Althoughinter-symbol interference occurs between temporally continuous symbols,and a reception apparatus side requires special signal processing toreceive FTN signals, such a configuration makes it possible to improvefrequency use efficiency in accordance with the way to narrow symbolintervals. Note that FTN has a considerable advantage that it ispossible to improve frequency use efficiency without extending afrequency band or increasing an antenna.

For example, FIG. 1 is an explanatory diagram for describing an exampleof transmission processing in the case where FTN is employed. Note that,as illustrated in FIG. 1, even in the case where FTN is employed, theprocessing up to adding an error correction code to and performingPSK/QAM modulation on a bit sequence is similar to the conventionaltransmission processing applied in the standards such as LTE/LTE-A. Inaddition, in the case where FTN is employed, as illustrated in FIG. 1,FTN mapping processing is performed on the bit sequence on which PSK/QAMmodulation has been performed. In the FTN mapping processing,over-sampling processing is performed on the bit sequence, and then awaveform shaping filter adjusts the symbol intervals beyond a Nyquistcriterion. Note that, the bit sequence on which FTN mapping processinghas been performed is subjected to digital/analog conversion, radiofrequency processing and the like, and sent to an antenna.

In addition, FIG. 2 is an explanatory diagram for describing an exampleof reception processing in the case where FTN is employed. A receptionsignal received at an antenna is subjected to radio frequencyprocessing, analog/digital conversion and the like, and then FTNde-mapping processing is performed thereon. In the FTN de-mappingprocessing, a matched filter corresponding to a waveform shaping filteron a transmission side, downsampling, whitening processing of residualnoise, and the like are performed on a reception signal converted into adigital signal. Note that channel equalization processing is performedon the digital signal (bit sequence) on which FTN de-mapping processinghas been performed, and then the processing from de-mapping to errorcorrection decoding is performed for an attempt to decode a transmissionbit sequence similarly to the conventional reception processing appliedin the standards such as LTE/LTE-A.

Note that, in the following description, it will be assumed that thesimple term “FTN processing” in transmission processing represents FTNmapping processing. Similarly, it will be assumed that the simple term“FTN processing” in reception processing represents FTN de-mappingprocessing. In addition, the transmission processing and the receptionprocessing described above with reference to FIGS. 1 and 2 are merelyexamples, but are not necessarily limited to the contents. For example,various kinds of processing accompanying the application of MIMO,various kinds of processing for multiplexing, and the like may beincluded.

With reference to FIGS. 1 and 2, the above describes the overview ofFTN.

2. Technical Problem

Next, a technical problem according to an embodiment of the presentdisclosure will be described.

As described above, FTN is capable of improving frequency use efficiencywithout extending a band or increasing the number of antennas.Meanwhile, in the case where FTN is applied, as described above,inter-symbol interference occurs between temporally continuous symbolsin the process of modulation. Therefore, signal processing (i.e., FTNde-mapping processing) for receiving FTN signals is necessary on areception apparatus side. Therefore, it can be assumed that simplyemploying FTN alone excessively increases the load on a receptionapparatus in FTN de-mapping processing, and deteriorates thecommunication quality of the overall system, for example, depending onthe state or condition of communication, the performance of thereception apparatus, or the like (which will be collectively referred toas “communication environment” below in some cases).

Accordingly, the present disclosure proposes an example of a mechanismcapable of adaptively adjusting a symbol interval in a more favorablemanner in accordance with a communication environment in the case whereFTN is applied.

3. Schematic Configuration of System

First, the schematic configuration of a system 1 according to anembodiment of the present disclosure will be described with reference toFIG. 3. FIG. 3 is an explanatory diagram illustrating an example of theschematic configuration of the system 1 according to an embodiment ofthe present disclosure. With reference to FIG. 3, the system 1 includesa base station 100 and a terminal apparatus 200. Here, the terminalapparatus 200 is also referred to as user. The user can also be referredto as user equipment (UE). Here, the UE may be a UE defined in LTE orLTE-A, or may generally refer to a communication apparatus.

(1) Base Station 100

The base station 100 is a base station of a cellular system (or mobilecommunication system). The base station 100 performs radio communicationwith a terminal apparatus (e.g., terminal apparatus 200) positioned in acell 10 of the base station 100. For example, the base station 100transmits a downlink signal to a terminal apparatus and receives anuplink signal from the terminal apparatus.

(2) Terminal Apparatus 200

The terminal apparatus 200 can perform communication in a cellularsystem (or mobile communication system). The terminal apparatus 200performs radio communication with a base station (e.g., base station100) of the cellular system. For example, the terminal apparatus 200receives a downlink signal from a base station and transmits an uplinksignal to the base station.

(3) Adjustment of Symbol Intervals

Especially in an embodiment of the present disclosure, when transmittingdata to the terminal apparatus 200, the base station 100 adjusts thesymbol intervals between the symbols of the data. More specifically, thebase station 100 performs FTN mapping processing on a bit sequence oftransmission target data on a downlink to adjust the symbol intervalsbetween the symbols of the data beyond a Nyquist criterion (i.e., makean adjustment such that the symbol intervals are narrower). In thiscase, for example, the terminal apparatus 200 performs demodulation anddecoding processing including FTN de-mapping processing on a receptionsignal from the base station 100 to attempt to decode the datatransmitted from the base station 100.

In addition, in an amplifier link, the symbol intervals between symbolsbased on FTN processing may be adjusted. In this case, the terminalapparatus 200 performs FTN mapping processing on a bit sequence oftransmission target data to adjust the symbol intervals between thesymbols of the data. In addition, the base station 100 performsdemodulation and decoding processing including FTN de-mapping processingon a reception signal from the terminal apparatus 200 to attempt todecode the data transmitted from the terminal apparatus 200.

The above describes the schematic configuration of the system 1according to an embodiment of the present disclosure with reference toFIG. 3.

4. Configuration of Each Apparatus

Next, with reference to FIGS. 4 and 5, the configurations of the basestation 100 and the terminal apparatus 200 according to an embodiment ofthe present disclosure will be described.

<4.1. Configuration of Base Station>

First, with reference to FIG. 4, an example of the configuration of thebase station 100 according to an embodiment of the present disclosurewill be described. FIG. 4 is a block diagram illustrating an example ofthe configuration of the base station 100 according to an embodiment ofthe present disclosure. As illustrated in FIG. 4, the base station 100includes an antenna unit 110, a radio communication unit 120, a networkcommunication unit 130, a storage unit 140, and a processing unit 150.

(1) Antenna Unit 110

The antenna unit 110 emits a signal output by the radio communicationunit 120 to the space as a radio wave. In addition, the antenna unit 110converts a radio wave in the space into a signal and outputs the signalto the radio communication unit 120.

(2) Radio Communication Unit 120

The radio communication unit 120 transmits and receives signals. Forexample, the radio communication unit 120 transmits a downlink signal toa terminal apparatus and receives an uplink signal from the terminalapparatus.

(3) Network Communication Unit 130

The network communication unit 130 transmits and receives information.For example, the network communication unit 130 transmits information toanother node and receives information from the other node. For example,the other node includes another base station and a core network node.

(4) Storage Unit 140

The storage unit 140 temporarily or permanently stores programs andvarious kinds of data for the operation of the base station 100.

(5) Processing Unit 150

The processing unit 150 provides the various functions of the basestation 100. For example, the processing unit 150 may further includeother components in addition to these components. Note that theprocessing unit 150 can further include other components in addition tothese components. That is, the processing unit 150 can also performoperations other than the operations of these components.

The communication processing unit 151 and the notification unit 153 willbe described in detail below. The above describes an example of theconfiguration of the base station 100 according to an embodiment of thepresent disclosure with reference to FIG. 4.

<4.2. Configuration of Terminal Apparatus>

Next, an example of the configuration of the terminal apparatus 200according to an embodiment of the present disclosure will be describedwith reference to FIG. 5. FIG. 5 is a block diagram illustrating anexample of the configuration of the terminal apparatus 200 according toan embodiment of the present disclosure. As illustrated in FIG. 5, theterminal apparatus 200 includes an antenna unit 210, a radiocommunication unit 220, a storage unit 230, and a processing unit 240.

(1) Antenna Unit 210

The antenna unit 210 emits a signal output by the radio communicationunit 220 to the space as a radio wave. In addition, the antenna unit 210converts a radio wave in the space into a signal and outputs the signalto the radio communication unit 220.

(2) Radio Communication Unit 220

The radio communication unit 220 transmits and receives signals. Forexample, the radio communication unit 220 receives a downlink signalfrom a base station and transmits an uplink signal to the base station.

(3) Storage Unit 230

The storage unit 230 temporarily or permanently stores programs andvarious kinds of data for the operation of the terminal apparatus 200.

(4) Processing Unit 240

The processing unit 240 provides the various functions of the terminalapparatus 200. For example, the processing unit 240 includes aninformation acquisition unit 241 and a communication processing unit243. Note that the processing unit 240 can further include othercomponents in addition to these components. That is, the processing unit240 can also perform operations other than the operations of thesecomponents.

The information acquisition unit 241 and the communication processingunit 243 will be described in detail below. The above describes anexample of the configuration of the terminal apparatus 200 according toan embodiment of the present disclosure with reference to FIG. 5.

5. Technical Features

Next, technical features according to an embodiment of the presentembodiment will be described with reference to FIGS. 6 to 23.

(1) Example of Time Resource Configuration

First, with reference to FIG. 6, an example of the configuration of atime resource in the case where FTN is supported will be described. FIG.6 is an explanatory diagram for describing an example of theconfiguration of a time resource in the case where FTN is supported.

In the example illustrated in FIG. 6, a time resource is divided intounits referred to as radio frames along a time-axis direction. Inaddition, a radio frame is divided into a predetermined number ofsubframes along the time-axis direction. Note that, in the exampleillustrated in FIG. 6, a radio frame includes ten subframes. Note that atime resource is allocated to a user in units of subframes.

In addition, a subframe is divided into a predetermined number of unitsreferred to as symbol blocks further along the time-axis direction. Forexample, in the example illustrated in FIG. 6, a subframe includesfourteen symbol blocks. A symbol block has a sequence portion includingsymbols for sending data, and a CP portion in which a part of thesequence is copied. In addition, as another example, a symbol block mayhave a sequence portion including symbols for sending data, and asequence portion (so-called pilot symbols) including known symbols. Notethat a CP or a pilot symbol can function, for example, as a guardinterval.

With reference to FIG. 6, the above describes an example of theconfiguration of a time resource in the case where FTN is supported.

(2) Example of Processing in Transmission Apparatus

Next, with reference to FIGS. 7 to 10, an example of processing in atransmission apparatus that supports FTN will be described. FIGS. 7 to10 are explanatory diagrams each for describing an example of theprocessing in the transmission apparatus that supports FTN. In theexamples illustrated in FIGS. 7 to 10, it is assumed that FTN signalsare transmitted to one or more users (i.e., the number N_(U) of users(or the number of reception apparatuses)≥1). In addition, in theexamples illustrated in FIGS. 7 to 10, multi-antenna transmission isassumed (i.e., the number NAY of transmission antenna ports (or thenumber of transmission antennas)≥1). Note that the transmissionapparatus in the present description can correspond to both the basestation 100 and the terminal apparatus 200. That is, on a downlink, thebase station 100 corresponds to the transmission apparatus, and chieflythe communication processing unit 151 in the base station 100 executesprocessing described below. In addition, on an uplink, the terminalapparatus 200 corresponds to the transmission apparatus, and chiefly thecommunication processing unit 243 in the terminal apparatus 200 executesprocessing described below. Note that the terminal apparatus 200corresponds to a reception apparatus on a downlink, and the base station100 corresponds to a reception apparatus on an uplink.

Specifically, in the examples illustrated in FIGS. 7 and 8, for example,the respective bit sequences (e.g., transport blocks) of a user A, auser B, and a user C are processed. For each of these bit sequences,some processing such as cyclic redundancy check (CRC) encoding, forwarderror correction (FEC) encoding, rate matching, andscrambling/interleaving), for example, as illustrated in FIG. 7 isperformed, and then modulation is performed. As illustrated in FIG. 8,layer mapping, power allocation, precoding, and SPC multiplexing arethen performed, and a bit sequence of each antenna element is output.Here, description will be made, assuming that the respective bitsequences corresponding to an antenna p1, an antenna p2, and an antennap3 are output.

As illustrated in FIG. 9, discrete Fourier transform (DFT)/fast Fouriertransform (FFT), resource element mapping, inverse discrete Fouriertransform (IDFT)/inverse fast Fourier transform (IFFT), cyclic prefix(CP) insertion, and the like are performed on the respective bitsequences corresponding to the antenna p1, the antenna p2, and theantenna p3, and a symbol sequence of each antenna element to which a CPhas been added is output. As illustrated in FIG. 10, as FTN processing,over-sampling and pulse shaping are then performed on the symbolsequence to which a CP has been added, and the output thereof isconverted from digital to analog and radio frequency (RF).

Note that the processing of the transmission apparatus described withreference to FIGS. 7 to 10 is merely an example, but is not necessarilylimited to the contents. For example, the transmission apparatus may bea transmission apparatus for which single antenna transmission isassumed. In this case, corresponding part of each processing describedabove may be replaced as appropriate.

With reference to FIGS. 7 to 10, the above describes an example ofprocessing in a transmission apparatus that supports FTN.

(3) Transmission Signal Processing

Next, an example of transmission signal processing in the case where FTNis employed will be described. Note that, in the present description, amulti-cell system such as a heterogeneous network (HetNet) or a smallcell enhancement (SCE) is assumed.

First, in the present description, it is assumed that an indexcorresponding to a subframe is omitted unless otherwise stated. Inaddition, in the case where the index of a transmission apparatus i andthe index of a reception apparatus u are respectively set as i and u,the indexes i and u may be indexes that represent the IDs of the cellsto which the corresponding apparatuses belong, or the IDs of the cellsthat are managed by the corresponding apparatuses.

Here, a bit sequence transmitted in a certain subframe t from thetransmission apparatus i to the reception apparatus u is set as b_(i,u).This bit sequence may be a bit sequence included in one transport block.In addition, description will be made in the present description, using,as an example, the case where one bit sequence is transmitted from thetransmission apparatus i to the reception apparatus u. However, aplurality of bit sequences may be transmitted from the transmissionapparatus i to the reception apparatus u, and the plurality of bitsequences may be included in a plurality of transport blocks andtransmitted at that time.

First, processing such as encoding for CRC, FEC encoding (convolutionalcode, turbo code, LDPC code, or the like), rate matching for adjustingan encoding rate, bit scrambling, and bit interleaving is performed onthe transmission target bit sequence Note that, in the case where eachof these kinds of processing is used as a function, the bit sequences onwhich the respective kinds of processing have been performed areexpressed as follows.

b _(CRC,i,u)=CRC_(ENC)(b _(i,u) ,u,i,t)

b _(FEC,i,u)=FEC_(ENC)(b _(CRC,i,u) ,u,i,t)

b _(RM,i,u)=RM(b _(FEC,i,u) ,u,i,t)

b _(SCR,i,u)=SCR(b _(RM,i,u) ,u,i,t)

b _(INT,i,u)=π(b _(SCR,i,u) ,u,i,t)  [Math. 1]

The bit sequence (e.g., bit sequence b_(INT,i,u)) on which theabove-described bit processing has been performed is mapped to a complexsymbol s (e.g., BPSK, QPSK, 8PSK, 16QAM, 64QAM, 256QAM, or the like),and further mapped to a spatial layer 1. Here, if the number of spatiallayers for the reception apparatus u is represented as N_(SL,i,u), thetransmission signal to which the bit sequence b_(INT,i,u) has beenmapped can be expressed in the form of a vector as follows.

$\begin{matrix}{{s_{i,u} = \begin{bmatrix}s_{i,u,0} \\\vdots \\s_{i,u,N_{{SL},i,u} - 1}\end{bmatrix}}{s_{i,u,l} = \begin{bmatrix}s_{i,u,l,0} & \ldots & s_{i,u,l,{N - 1}}\end{bmatrix}}} & \left\lbrack {{Math}.\mspace{11mu} 2} \right\rbrack\end{matrix}$

Note that, in the equation shown above, each element of a vectorS_(i,u,j) corresponds to the complex symbol s to which the bit sequenceb_(INT,i,u) is mapped.

Next, the respective kinds of processing of power allocation andprecoding are performed on the transmission signal that has been mappedto the spatial layer. Here, in the case where the number of antennaports (or the number of transmission antennas) in the transmissionapparatus i is represented as N_(AP,i), the transmission signal on whichpower allocation and precoding have been performed is shown as avectorx_(i,u) below.

$\begin{matrix}{\begin{matrix}{x_{i,u} = {W_{i,u}P_{i,u}s_{i,u}}} \\{= \begin{bmatrix}x_{i,u,0,0} & \ldots & x_{i,u,0,{N_{{EL},{TTL}} - 1}} \\\vdots & \ddots & \vdots \\x_{i,u,{N_{AP} - 1},0} & \ldots & x_{i,u,N_{AP} - 1,N_{{EL},{TTL}} - 1}\end{bmatrix}} \\{= \begin{bmatrix}x_{i,u,0} \\\vdots \\x_{i,u,{N_{AP} - 1}}\end{bmatrix}}\end{matrix}{x_{i,u,p} = \begin{bmatrix}x_{i,u,p,0} & \ldots & x_{i,u,p,{N_{{EL},{TTL}} - 1}}\end{bmatrix}}{W_{i,u} = \begin{bmatrix}w_{i,u,0,0} & \ldots & w_{i,u,0,{N_{{SL},i,u} - 1}} \\\vdots & \ddots & \vdots \\w_{i,u,{N_{{AP},i} - 1},0} & \ldots & w_{i,u,N_{{AP},i} - 1,N_{{SL},i,u} - 1}\end{bmatrix}}{P_{i,u} = \begin{bmatrix}P_{i,u,0,0} & \ldots & P_{i,u,0,{N_{{SL},i,u} - 1}} \\\vdots & \ddots & \vdots \\P_{i,u,{N_{{SL},i,u} - 1},0} & \ldots & P_{i,u,,{N_{{SL},i,u} - 1},{N_{{SL},i,u} - 1}}\end{bmatrix}}} & \left\lbrack {{Math}.\mspace{11mu} 3} \right\rbrack\end{matrix}$

Note that, in the equation shown above, a matrix W_(i,u) is a precodingmatrix for the reception apparatus u. It is desirable that an element inthis matrix be a complex number or a real number. In addition, a matrixP_(i,u) is a power allocation coefficient matrix for transmitting asignal from the transmission apparatus i to the reception apparatus u.In this matrix, it is desirable that each element be a positive realnumber. Note that this matrix P_(i,u) may be a diagonal matrix (i.e.,matrix in which the components other than the diagonal components are 0)as described below.

$\begin{matrix}{P_{i,u} = \begin{bmatrix}P_{i,u,0,0} & 0 & \ldots & 0 \\0 & P_{i,u,1,1} & \ddots & \vdots \\\vdots & \ddots & \ddots & 0 \\0 & \ldots & \ldots & P_{i,u,,{N_{{SL},u} - 1},{N_{{SL},u} - 1}}\end{bmatrix}} & \left\lbrack {{Math}.\mspace{11mu} 4} \right\rbrack\end{matrix}$

Here, a communication target of the transmission apparatus i is notlimited to only the reception apparatus u, but can also be anotherreception apparatus v. Therefore, for example, a signal x_(i,u) directedto the reception apparatus u and a signal x_(i,v) directed to the otherreception apparatus v can be transmitted in the same radio resource.These signals are multiplexed for each transmission antenna port, forexample, on the basis of superposition multiplexing, superpositioncoding (SPC), multiuser superpositoin transmission (MUST),non-orthogonal multiple access (NOMA), or the like. A multiplexed signalx_(i) transmitted from the transmission apparatus i is expressed asfollows.

$\begin{matrix}{x_{i} = {\sum\limits_{u \in U_{i}}x_{i,u}}} & \left\lbrack {{Math}.\mspace{11mu} 5} \right\rbrack\end{matrix}$

Note that, in the equation shown above, U_(i) represents a set ofindexes of the reception apparatus u for which the transmissionapparatus i multiplexes signals. In addition, the following processingwill be described, focusing on signal processing for each transmissionantenna port p and each symbol block g.

A signal for each transmission antenna port is converted into afrequency component by performing time-frequency transform processing(e.g., DFT, FFT, or the like) on a time symbol sequence. Here, if thenumber of data symbols included in the symbol block g is represented asN_(DS,g), a frequency component x⁻ _(i,p,g) of a time symbol sequencex_(i,p,g) of the symbol block g transmitted from the transmissionapparatus i via a transmission port p can be expressed as follows. Notethat, in the present description, it is assumed that “x⁻” represents aletter obtained by overlining “x.” In addition, it is assumed that FNshown in the following equation represents a Fourier transform matrixhaving size N.

$\begin{matrix}{\begin{matrix}{{\overset{\;}{\mspace{79mu} x}}_{i,p,g} = {F_{N_{{DS},g}}x_{i,p,g}^{T}}} \\{= \begin{bmatrix}{\overset{\_}{x}}_{i,p,g,0} & \ldots & {\overset{\_}{x}}_{i,p,g,{N_{{DS},g} - 1}}\end{bmatrix}^{T}}\end{matrix} {x_{i,p,g} = \begin{bmatrix}x_{i,p,g,0} & \ldots & x_{i,p,g,{N_{{DS},g} - 1}}\end{bmatrix}}{F_{N} = \mspace{31mu} \begin{bmatrix}{\exp \; \left( {{- j}\; 2\pi \frac{0 \cdot 0}{N}} \right)} & \ldots & {\exp \; \left( {{- j}\; 2\pi \frac{0 \cdot \left( {N - 1} \right)}{N}} \right)} \\\vdots & \ddots & \vdots \\{\exp \; \left( {{- j}\; 2\pi \frac{\left( {N - 1} \right) \cdot 0}{N}} \right)} & \ldots & {\exp \; \left( {{- j}\; 2\pi \frac{\left( {N - 1} \right) \cdot \left( {N - 1} \right)}{N}} \right)}\end{bmatrix}}} & \left\lbrack {{Math}.\mspace{11mu} 6} \right\rbrack\end{matrix}$

A converted frequency component x⁻ _(i,p,g) is mapped to a resourceelement along the frequency direction of a resource block. It is alsopossible to process this processing of mapping the frequency componentx⁻ _(i,p,g) to a resource element as shown in the following equation.

$\begin{matrix}\begin{matrix}{{\overset{\sim}{x}}_{i,p,g} = {A_{i,p,g}{\overset{\_}{x}}_{i,p,g}}} \\{= \begin{bmatrix}{\overset{\sim}{x}}_{i,p,g,0} & \ldots & {\overset{\sim}{x}}_{i,p,g,{N_{IDFT} - 1}}\end{bmatrix}^{T}}\end{matrix} & \left\lbrack {{Math}.\mspace{11mu} 7} \right\rbrack\end{matrix}$

Note that, in the equation shown above, x^(˜) _(i,p,g) represents afrequency component after the frequency component x⁻ _(i,p,g) is mappedto a resource element. Note that, in the present description, it isassumed that “x^(˜)” represents a letter obtained by providing tilde tothe top of “x.” In addition, in the equation shown above, A represents afrequency mapping matrix having size N_(IDFT)×N_(DS,g). Here, in thecase where a frequency component x⁻ _(i,p,g,k′) of a component k′ afterfrequency conversion is mapped to a frequency component x^(˜) _(i,p,g,k)corresponding to a component k, a (k, k′) component of a frequencymapping matrix is 0. It is desirable that the sum of the elements ineach row of the matrix A be less than or equal to 1, and the sum of theelements in each column be less than or equal to 1.

Next, frequency-time conversion processing (e.g., IDFT, IFFT, or thelike) is performed on the frequency component x^(˜) _(i,p,g) mapped to aresource element, the frequency component x^(˜) _(i,p,g) is convertedinto a time sequence again. Here, a time symbol sequence d^(˜) _(i,p,g)into which x^(˜) _(i,p,g) is converted is expressed as follows. Notethat, in the present description, it is assumed that “d^(˜)” representsa letter obtained by providing tilde to the top of “d.” In addition, inthe equation shown below, F^(H) represents a Hermitian matrix of F.

$\begin{matrix}\begin{matrix}{{\overset{\sim}{d}}_{i,p,g} = {F_{N_{IDFT}}^{H}{\overset{\sim}{x}}_{i,p,g}}} \\{= \begin{bmatrix}{{\overset{\sim}{d}}_{i,p,g,}(0)} & \ldots & {{\overset{\sim}{d}}_{i,p,g,}\left( {N_{IDFT} - 1} \right)}\end{bmatrix}^{T}}\end{matrix} & \left\lbrack {{Math}.\mspace{11mu} 8} \right\rbrack\end{matrix}$

In addition, a CP or a known symbol sequence is added for each symbolblock to the time symbol sequence d^(˜) _(i,p,g) converted from afrequency component to a time sequence. For example, in the case where aCP having length N_(CP,g) is added to the time symbol sequence a symbolsequence d{circumflex over ( )}_(i,p,g) to which a CP has been added isexpressed as follows. Note that it is assumed that “d{circumflex over( )}” represents a letter obtaining by providing a hat to “d.”

$\begin{matrix}\begin{matrix}{{\hat{d}}_{i,p,g} = \begin{bmatrix}{{\hat{d}}_{i,p,g,}(0)} & \ldots & {{\hat{d}}_{i,p,g,}\left( {N_{{IDFT},g} + N_{{CP},g} - 1} \right)}\end{bmatrix}^{T}} \\{= \left\lbrack \begin{matrix}{{\overset{\sim}{d}}_{i,p,g,}\left( {N_{{IDFT},g} - N_{{CP},g}} \right)} & \ldots\end{matrix} \right.} \\\left. {\begin{matrix}{{\overset{\sim}{d}}_{i,p,g,}\left( {N_{{IDFT},g} - 1} \right)} & {{\overset{\sim}{d}}_{i,p,g,}(0)} & \ldots\end{matrix}{{\overset{\sim}{d}}_{i,p,g,}\left( {N_{{IDFT},g} - 1} \right)}} \right\rbrack^{T}\end{matrix} & \left\lbrack {{Math}.\mspace{11mu} 9} \right\rbrack\end{matrix}$

Next, FTN processing is performed on the symbol sequence d{circumflexover ( )}_(i,p,g) to which a CP has been added. Note that the FTNprocessing includes over-sampling processing and pulse shaping filteringprocessing. First, focus is placed on over-sampling processing. If thenumber of over-samples is represented as Nos, a time symbol sequenced′_(i,p)[n] after over-sampling is expressed as follows. Note that, inthe equation shown below, an index g of a symbol block is omitted.

$\begin{matrix}{{d_{i,p}^{\prime}\lbrack n\rbrack} = \left\{ \begin{matrix}{{{\hat{d}}_{i,p}\left( \frac{n}{N_{OS}} \right)},} & {{n = 0},N_{OS},{2\; N_{OS}},\ldots} \\{0,} & {otherwise}\end{matrix} \right.} & \left\lbrack {{Math}.\mspace{11mu} 10} \right\rbrack\end{matrix}$

In addition, pulse shaping processing that takes FTN into considerationis performed on the time symbol sequence d′_(i,p)[n] afterover-sampling. In the case where the filter factor of a pulse shapefilter is represented as Ψ_(i,p)(t), an output of pulse shapingprocessing is expressed as follows.

$\begin{matrix}{{s_{i,p}(t)} = {\sum\limits_{n}{{d_{i,p}^{\prime}\lbrack n\rbrack}{\psi_{i,p}\left( {t - {n\; \tau_{i,p}T}} \right)}}}} & \left\lbrack {{Math}.\mspace{11mu} 11} \right\rbrack\end{matrix}$

Here, in the case where the symbol length is represented as T, 1/Trepresents the symbol rate. In addition, τ_(i,p) is a coefficientregarding FTN, and has a real-number value within a range of0<τ_(i,p)≤1. Note that, in the following description, the coefficientτ_(i,p) will be referred to as “compression coefficient” for the sake ofconvenience in some cases. It is also possible to regard the compressioncoefficient as a coefficient that connects the symbol length T to asymbol arrangement (i.e., symbol intervals) T′ in FTN. In general,0<T′≤T holds, and a relationship of τ_(i,p)=T′/T≤1 is obtained.

Note that, in the conventional modulation scheme applied in thestandards such as LTE/LTE-A, it is preferable that the filter factor bea filter (what is called, a filter (Nyquist filter) compliant with aNyquist criterion) of a coefficient that has a value of zero per time Twhen the value at time zero peaks. A specific example of the filtercompliant with a Nyquist criterion includes a raised-cosine (RC) filter,a root-raised-cosine (RRC) filter, and the like. Note that, in the casewhere a filter compliant with a Nyquist criterion in the above-describedtransmission processing in which FTN can be applied, τ_(i,p)=1 makes theinter-symbol interference of the generated signal itself zero inprinciple.

Analog and radio frequency (RF) processing is then performed on thesignal (i.e., output of pulse shaping filtering processing) on which FTNprocessing has been performed, and the signal is sent to an transmissionantenna (antenna port).

The above describes an example of transmission signal processing in thecase where FTN is employed.

(4) FTN Transmission Scheme in which Changing Compression Coefficientfor Each Cell (Cell-Specific)

Next, an example of a transmission scheme in the case where thecompression coefficient τ_(i,p) in FTN is changed for each cell(cell-specific) will be described.

In FTN, as the compression coefficient τ_(i,p) decreases, the influenceof inter-symbol interference contained in FTN itself increases (in otherwords, the symbol intervals are narrower). Meanwhile, in the so-calledradio communication system, multiplex transmission, the nonlinearfrequency characteristic of a propagation path, and the like can causeinter-symbol interference even in a radio propagation path. Therefore,in the radio communication system in which FTN is employed, it can benecessary to take the inter-symbol interference in the radio propagationpath into consideration in addition to the influence of inter-symbolinterference contained in FTN itself. In view of such circumstances, thecommunication system according to the present embodiment takes intoconsideration the load of the processing of addressing inter-symbolinterference in a reception apparatus, and is configured to be capableof adaptively adjusting a compression coefficient. Such a configurationmakes it possible to balance between the load in a reception apparatusand frequency use efficiency.

(a) Adjustment of Compression Coefficient According to Frequency ofChannel

First, with reference to FIGS. 11 and 12, an example of the case where acompression coefficient is adjusted in accordance with the frequency ofa channel will be described.

For example, FIG. 11 illustrates an example of the relationship betweenthe frequency of a channel, the level of inter-symbol interference, anda compression coefficient. In general, the delay spread caused by aradio propagation path increases as frequency is lower because of theinfluence of a reflected wave, a diffracted wave, and the like, whilethe delay spread decreases as frequency is higher because of itstendency to propagate more straightly. That is, the influence of theinter-symbol interference in the radio propagation path tends toincrease as frequency is lower, and decrease as frequency is higher.

It is estimated from such a characteristic that even the processing ofaddressing the inter-symbol interference in the radio propagation pathimposes a relatively lighter load in a channel of high frequency.Therefore, the load that is no longer spent in addressing theinter-symbol interference in the radio propagation path is spent in theprocessing of addressing inter-symbol interference contained in FTN.This makes it possible to suppress increase in the load in a receptionapparatus and efficiently improve frequency use efficiency.

Specifically, as illustrated in FIG. 11, it is desirable to employ theconfiguration in which a smaller compression coefficient is applied to achannel of higher frequency (in other words, the configuration in whicha larger compression coefficient is applied to a channel of lowerfrequency).

As a more specific example, FIG. 11 illustrates an example of the casewhere a component carrier (CC) 0 to a CC 3 are used as CCs for atransmission apparatus to transmit data. Note that, in the case wherethe respective frequency channels corresponding to the CC 0 to the CC 3are represented as channels f0 to f3, it is assumed that the magnituderelationship between the channels f0 to f3 with respect to frequency isf0<f1<f2<f3. Note that, in the example illustrated in FIG. 11, it isassumed that the CC 0 is set as a primary CC (PCC), and the CC 1 to theCC 3 are each set as a secondary CC (SCC).

Here, in the case where the respective compression coefficients appliedin the CC 0 to the CC 3 are represented as τ0 to τ3, the magnituderelationship between the compression coefficients τ0 to τ3 in theexample illustrated in FIG. 11 is τ0≥τ1≥τ2≥τ3.

Next, with reference to FIG. 12, an example of processing of setting acompression coefficient in accordance with the frequency of a channelwill be described. FIG. 12 is a flowchart illustrating an example ofprocessing of setting a compression coefficient in accordance with thefrequency of a channel. Note that, in the present description,description will be made using the case where a transmission apparatusplays a main role to set a compression coefficient as an example.Meanwhile, the main role of the processing is not necessarily limited toa transmission apparatus. As a specific example, in the case where FTNis applied to an uplink, a base station corresponding to a receptionapparatus may set a compression coefficient.

Specifically, a transmission apparatus first checks the frequency bandof a target CC (S101). The transmission apparatus then just has to setthe compression coefficient corresponding to the target CC in accordancewith the frequency band of the CC (S103).

With reference to FIGS. 11 and 12, the above describes an example of thecase where a compression coefficient is adjusted in accordance with thefrequency of a channel.

(b) Adjustment of Compression Coefficient according to Component Carrier

Next, with reference to FIGS. 13 and 14, an example of the case where acompression coefficient is adjusted in accordance with whether a targetCC is a PCC or an SCC will be described.

For example, FIG. 13 illustrates another example of the relationshipbetween the frequency of a channel, the level of inter-symbolinterference, and a compression coefficient. It is desirable that PCCsbe placed in the state in which it is basically possible for all theterminals in a cell to transmit and receive the PCCs. In addition, fromthe perspective of coverage, it is desirable that a PCC be as low afrequency channel as possible. For example, in the example illustratedin FIG. 11, the PCC is the lowest frequency channel among the targets.Note that the PCC corresponds to an example of a CC of higher priority.

Because of the above-described characteristic of a PCC, it is moredesirable to apply a larger value than that of another CC (SCC) to thecompression coefficient corresponding to the PCC in order to lessen theinter-symbol interference caused by FTN. Moreover, setting a compressioncoefficient of 1 (τ=1) for the PCC also makes it possible to furtherimprove the reliability of the transmission and reception of data viathe PCC. Note that setting 1 as the compression coefficient issubstantially the same as applying no FTN. In principle, theinter-symbol interference accompanying FTN processing does not occur.

For example, FIG. 13 illustrates an example of the case where the CC 0to the CC 3 are used as CCs. Note that, in the case where the respectivefrequency channels corresponding to the CC 0 to the CC 3 are representedas channels f0 to f3, it is assumed that the magnitude relationshipbetween the channels f0 to f3 with respect to frequency is f0<f1<f2<f3.Note that, in the example illustrated in FIG. 11, it is assumed that theCC 1 is set as a primary CC (PCC), and the CC 0, CC 2, and the CC 3 areeach set as a secondary CC (SCC). That is, FIG. 13 illustrates anexample of the case where the PCC is not the lowest frequency channelamong the targets. Note that the respective compression coefficientsapplied in the CC 0 to the CC 3 are represented as τ0 to τ3.

Specifically, in the case of the example illustrated in FIG. 13, thecompression coefficient τ1 applied in the PCC (i.e., channel f1) is setto be the highest (e.g., 1 is set therefor), and the compressioncoefficients τ0, τ2, and τ3 applied in the other CCs (SCCs) are set tobe less than or equal to the compression coefficient τ1. Such aconfiguration makes it possible to secure the reliability of thetransmission and reception of data via the PCC. Note that, as themagnitude relationship between the compression coefficients τ0, τ2, andτ3, smaller compression coefficients may be set with increase infrequency similarly to the example illustrated in FIG. 11.

Next, with reference to FIG. 14, an example of processing of setting acompression coefficient in accordance with whether a target CC is a PCCor an SCC will be described. FIG. 14 is a flowchart illustrating anexample of processing of setting a compression coefficient in accordancewith whether a target CC is a PCC or an SCC. Note that, in the presentdescription, description will be made using the case where atransmission apparatus plays a main role to set a compressioncoefficient as an example.

Specifically, a transmission apparatus first determines whether or not atarget CC is a PCC (i.e., any of PCC and SCC) (S151). In the case wherethe target CC is a PCC (S151, YES), the transmission apparatus sets acompression coefficient (e.g., τ=1) for a PCC as the compressioncoefficient corresponding to the CC (S153). In addition, in the casewhere the target CC is not a PCC (S151, NO), the transmission apparatuschecks the frequency band of the CC (S155). The transmission apparatusthen sets the compression coefficient corresponding to the target CC inaccordance with the frequency band of the CC (S157).

With reference to FIGS. 13 and 14, the above describes an example of thecase where a compression coefficient is adjusted in accordance withwhether a target CC is a PCC or an SCC.

(c) Example of Control Table for Setting Compression Coefficient

Next, an example of a control table for the subject (e.g., transmissionapparatus) that sets a compression coefficient to set a compressioncoefficient for a target CC as described above in accordance withwhether or not the CC is a PCC, or a condition of the CC such asfrequency will be described.

Specifically, as shown below as Table 1, the range of a frequency bandand the value of a compression coefficient may be associated with eachother in advance, and managed as a control table. In addition, in thecontrol table, the values of compression coefficients may beindividually set for a PCC and an SCC.

TABLE 1 Example of Association of Range of Frequency Band and Value ofCompression Coefficient Range of Frequency f of CC Primary CC SecondaryCC F0 ≤ f < Fl τpcell0 τpcell0 Fl ≤ f < F2 τpcell0 τpcell0 F2 ≤ f < F3τpcell0 τpcell0 F3 ≤ f < F4 τpcell0 τpcell0 — — —

For example, in the example shown above as Table 1, in the case where atarget CC is a PCC, compression coefficients τpcell0, τpcell1, τpcell2,τpcell4, . . . are set in accordance with the range of a frequency fcorresponding to the CC. Note that it is desirable at this time that themagnitude relationship between the respective compression coefficientsbe τpcell0≥τpcell1≥τpcell2≥τpcell4≥ . . . . Note that 1 may be set asthe compression coefficient corresponding to a PCC.

In addition, in the example shown above as Table 1, in the case where atarget CC is a SCC, compression coefficients τscell0, τscell1, τscell2,τscell4, . . . are set in accordance with the range of the frequency fcorresponding to the CC. Note that it is desirable at this time that themagnitude relationship between the respective compression coefficientsbe τscell0≥τscell1≥τscell2≥τscell4≥ . . . . In addition, it is desirablethat a smaller value than that of the compression coefficientcorresponding to a PCC be set as the compression coefficientcorresponding to an SCC.

(5) Example of Sequence for Changing Compression Coefficient for EachCell (Cell-Specific)

Next, an example of a communication sequence between the base station100 and the terminal apparatus 200 in the case where the compressioncoefficient τ_(i,p) in FTN is changed for each cell (cell-specific) willbe described.

(a) Regarding Application to Downlink

First, with reference to FIGS. 15 and 16, an example of a communicationsequence between the base station 100 and the terminal apparatus 200 inthe case where FTN is employed for a downlink will be described.

On a downlink, the base station 100 adjusts the symbol intervals betweensymbols in data transmitted via a shared channel (data channel) on thebasis of the compression coefficient τ_(i,p) decided for each cell. Inthis case, the base station 100 notifies the terminal apparatus 200 ofthe compression coefficient τ_(i,p) decided for each cell as a parameterrelated to FTN. This allows the terminal apparatus 200 to decode thedata (i.e., data on which FTN processing has been performed) transmittedfrom the base station 100 on the basis of the compression coefficientτ_(i,p) of which the terminal apparatus 200 is notified by the basestation 100.

Note that, as long as the terminal apparatus 200 is capable ofrecognizing the compression coefficient τ_(i,p) by the timing at whichthe data on which the base station 100 has performed FTN mappingprocessing on the basis of the compression coefficient τ_(i,p) isdecoded, the timing at which the base station 100 notifies the terminalapparatus 200 of an FTN parameter is not limited in particular. Forexample, an example of the timing at which the base station 100 notifiesthe terminal apparatus 200 of an FTN parameter includes RRC connectionreconfiguration, system information, downlink control information (DCI),and the like. Especially in the case where the compression coefficientτ_(i,p) is set for each cell (cell-specific), it is more desirable thatthe base station 100 notify the terminal apparatus 200 of thecompression coefficient τ_(i,p) in RRC connection reconfiguration orsystem information.

(a-1) Notification Through RRC Connection Reconfiguration

First, with reference to FIG. 15, as an example of a communicationsequence in the case where FTN is employed for a downlink, descriptionwill be made, focusing especially on an example of the case where thebase station 100 uses RRC connection reconfiguration to notify theterminal apparatus 200 of an FTN parameter. FIG. 15 is an explanatorydiagram for describing an example of a communication sequence in thecase where FTN is employed for a downlink, and illustrates an example ofthe case where the base station 100 uses RRC connection reconfigurationto notify the terminal apparatus 200 of an FTN parameter.

More specifically, when transmitting an RRC connection reconfigurationmessage to the terminal apparatus 200, the base station 100 notifies theterminal apparatus 200 of an FTN parameter (e.g., compressioncoefficient τ_(i,p)) set for each cell (S201). When receiving the RRCconnection reconfiguration message from the base station 100, theterminal apparatus 200 transmits an RRC connection reconfigurationcomplete message indicating that the terminal apparatus 200 hassucceeded in correctly receiving the message to the base station 100(S203). In this procedure, the terminal apparatus 200 becomes capable ofrecognizing the compression coefficient τ_(i,p) (i.e., compressioncoefficient τ_(i,p) for decoding (FTN de-mapping) the data transmittedfrom the base station 100) used by the base station 100 to perform FTNmapping processing on transmission data.

Next, the base station 100 uses a physical downlink control channel(PDCCH) to transmit allocation information of a physical downlink sharedchannel (PDSCH) that is the frequency (e.g., resource block (RB) andtime resource (e.g., subframe (SF)) of data transmission and receptionto the terminal apparatus 200 (S205). The terminal apparatus 200 thathas received the PDCCH decodes the PDCCH, thereby becoming capable ofrecognizing the frequency and time resource (PDSCH) allocated toterminal apparatus 200 itself (S207).

Next, the base station 100 performs various kinds of modulationprocessing including FTN mapping processing on transmission target dataon the basis of the FTN parameter set for each cell to generate atransmission signal, and transmits the transmission signal onto adesignated PDSCH resource (S209). The terminal apparatus 200 receivesthe PDSCH designated by the allocation information from the base station100, and performs various kinds of demodulation and decoding processingincluding FTN de-mapping processing based on the FTN parameter of whichthe terminal apparatus 200 has been notified by the base station 100 ona reception signal to extract the data transmitted from the base station100 (S211). Note that, in the case where the terminal apparatus 200 hassucceeded in decoding the data with no error on the basis of errordetection such as CRC, the terminal apparatus 200 may return an ACK tothe base station 100. In addition, in the case where the terminalapparatus 200 has detected an error on the basis of error detection suchas CRC, the terminal apparatus 200 may return a NACK to the base station100 (S213).

With reference to FIG. 15, the above makes, as an example of acommunication sequence in the case where FTN is employed for a downlink,description, focusing especially on an example of the case where thebase station 100 uses RRC connection reconfiguration to notify theterminal apparatus 200 of an FTN parameter.

(a-2) Notification Through System Information

Next, with reference to FIG. 16, as an example of a communicationsequence in the case where FTN is employed for a downlink, descriptionwill be made, focusing especially on an example of the case where thebase station 100 uses system information (SIB: system information block)to notify the terminal apparatus 200 of an FTN parameter. FIG. 16 is anexplanatory diagram for describing an example of a communicationsequence in the case where FTN is employed for a downlink, andillustrates an example of the case where the base station 100 usessystem information to notify the terminal apparatus 200 of an FTNparameter.

More specifically, the base station 100 broadcasts an SIB message toeach terminal apparatus 200 positioned in the cell 10. At this time, thebase station 100 includes an FTN parameter in the SIB message to notifyeach terminal apparatus 200 positioned in the cell 10 of the FTNparameter (S251). This allows the terminal apparatus 200 to recognizethe compression coefficient τ_(i,p) used by the base station 100 toperform FTN mapping processing on transmission data. Note that, asdescribed above, an SIB message is broadcast to each terminal apparatus200 positioned in the cell 10, so that the terminal apparatus 200 makesno response to the SIB message for the base station 100. In other words,in the example illustrated in FIG. 16, the base station 100unidirectionally notifies the terminal apparatus 200 positioned in thecell 10 of various kinds of parameter information (e.g., FTN parameter).

Note that the communication sequences represented by reference numeralsS253 to S261 in FIG. 16 are similar to the communication sequencesrepresented by reference numerals S205 to S213 in FIG. 15, so thatdetailed description will be omitted.

With reference to FIG. 16, the above makes, as an example of acommunication sequence in the case where FTN is employed for a downlink,description, focusing especially on an example of the case where thebase station 100 uses system information to notify the terminalapparatus 200 of an FTN parameter.

(b) Regarding Application to Uplink

Next, with reference to FIGS. 17 and 18, an example of a communicationsequence between the base station 100 and the terminal apparatus 200 inthe case where FTN is employed for an uplink will be described.

On an uplink, the terminal apparatus 200 serves as a transmissionapparatus, and the base station 100 serves as a reception apparatus.Meanwhile, on an uplink, the base station 100 takes charge in thenotification of an FTN parameter and the allocation of a physical uplinkshared channel ((PUSCH) resource similarly to a downlink. That is, inthe situation in which parameter setting set for each cell is performed(e.g., setting of an FTN parameter), it is more desirable in terms of anapparatus group in one area referred to as cell that the base station100 play the role of the notification of various kinds of informationand various kinds of control.

Note that, as long as the terminal apparatus 200 is capable ofrecognizing the compression coefficient τ_(i,p) applied to FTN mappingprocessing by the timing at which the FTN mapping processing isperformed on transmission target data, the timing at which the basestation 100 notifies the terminal apparatus 200 of an FTN parameter isnot limited in particular. For example, an example of the timing atwhich the base station 100 notifies the terminal apparatus 200 of an FTNparameter includes RRC connection reconfiguration, system information,downlink control information (DCI), and the like. Especially in the casewhere the compression coefficient τ_(i,p) is set for each cell(cell-specific), it is more desirable that the base station 100 notifythe terminal apparatus 200 of the compression coefficient τ_(i,p) in RRCconnection reconfiguration or system information.

(b-1) Notification Through RRC Connection Reconfiguration

First, with reference to FIG. 17, as an example of a communicationsequence in the case where FTN is employed for an uplink, descriptionwill be made, focusing especially on an example of the case where thebase station 100 uses RRC connection reconfiguration to notify theterminal apparatus 200 of an FTN parameter. FIG. 17 is an explanatorydiagram for describing an example of a communication sequence in thecase where FTN is employed for an uplink, and illustrates an example ofthe case where the base station 100 uses RRC connection reconfigurationto notify the terminal apparatus 200 of an FTN parameter.

More specifically, when transmitting an RRC connection reconfigurationmessage to the terminal apparatus 200, the base station 100 notifies theterminal apparatus 200 of an FTN parameter (e.g., compressioncoefficient τ_(i,p)) set for each cell (S301). When receiving the RRCconnection reconfiguration message from the base station 100, theterminal apparatus 200 transmits an RRC connection reconfigurationcomplete message indicating that the terminal apparatus 200 hassucceeded in correctly receiving the message to the base station 100(S303). In this procedure, the terminal apparatus 200 becomes capable ofrecognizing the compression coefficient τ_(i,p) used to perform FTNmapping processing on data to be transmitted to the base station 100.

Next, the terminal apparatus 200 uses a physical uplink control channel(PUCCH) to request the base station 100 in to allocate a physical uplinkshared channel (PUSCH) that is a frequency and time resource fortransmitting and receiving data. The base station 100 that has receivedthe PUCCH decodes the PUCCH to recognize the contents of the requestfrom the terminal apparatus 200 to allocate a frequency and timeresource (S305).

Next, the base station 100 uses a physical downlink control channel(PDCCH) to transmit allocation information of a PUSCH to the terminalapparatus 200 (S307). The terminal apparatus 200 that has received thePDCCH decodes the PDCCH, thereby becoming capable of recognizing thefrequency and time resource (PUSCH) allocated to terminal apparatus 200itself (S309).

Next, the terminal apparatus 200 performs various kinds of modulationprocessing including FTN mapping processing on transmission target dataon the basis of the FTN parameter of which the terminal apparatus 200has been notified by the base station 100 to generate a transmissionsignal. The terminal apparatus 200 then transmits the generatedtransmission signal onto the PUSCH resource designated by the allocationinformation from the base station 100 (S311). The base station 100receives the designated PUSCH, and performs various kinds ofdemodulation and decoding processing including the FTN de-mappingprocessing based on the FTN parameter set for each cell on a receptionsignal to extract the data transmitted from the terminal apparatus 200(S313). Note that, in the case where the base station 100 has succeededin decoding the data with no error on the basis of error detection suchas CRC, the base station 100 may return an ACK to the terminal apparatus200. In addition, in the case where the base station 100 has detected anerror on the basis of error detection such as CRC, the base station 100may return a NACK to the terminal apparatus 200 (S315).

With reference to FIG. 17, the above makes, as an example of acommunication sequence in the case where FTN is employed for an uplink,description, focusing especially on an example of the case where thebase station 100 uses RRC connection reconfiguration to notify theterminal apparatus 200 of an FTN parameter.

(b-2) Notification Through System Information

Next, with reference to FIG. 18, as an example of a communicationsequence in the case where FTN is employed for an uplink, descriptionwill be made, focusing especially on an example of the case where thebase station 100 uses system information to notify the terminalapparatus 200 of an FTN parameter. FIG. 18 is an explanatory diagram fordescribing an example of a communication sequence in the case where FTNis employed for an uplink, and illustrates an example of the case wherethe base station 100 uses system information to notify the terminalapparatus 200 of an FTN parameter.

More specifically, the base station 100 broadcasts an SIB message toeach terminal apparatus 200 positioned in the cell 10. At this time, thebase station 100 includes an FTN parameter in the SIB message to notifyeach terminal apparatus 200 positioned in the cell 10 of the FTNparameter (S351). This allows the terminal apparatus 200 to recognizethe compression coefficient τ_(i,p) used to perform FTN mappingprocessing on data to be transmitted to the base station 100. Note that,similarly to the case of a downlink, an SIB message is broadcast to eachterminal apparatus 200 positioned in the cell 10, so that the terminalapparatus 200 makes no response to the SIB message for the base station100. In other words, in the example illustrated in FIG. 18, the basestation 100 unidirectionally notifies the terminal apparatus 200positioned in the cell 10 of various kinds of parameter information(e.g., FTN parameter).

Note that the communication sequences represented by reference numeralsS353 to 5363 in FIG. 18 are similar to the communication sequencesrepresented by reference numerals S305 to S315 in FIG. 17, so thatdetailed description will be omitted.

With reference to FIG. 15, the above makes, as an example of acommunication sequence in the case where FTN is employed for an uplink,description will be made, focusing especially on an example of the casewhere the base station 100 uses system information to notify theterminal apparatus 200 of an FTN parameter.

(c) Regarding Application to Communication System in which CarrierAggregation is Employed

Next, an example of a communication sequence between the base station100 and the terminal apparatus 200 in the case where FTN is employed fora communication system in which carrier aggregation is employed will bedescribed.

In the above-described example of a communication sequence on an uplinkand a downlink, a frequency channel used for the notification of an FTNparameter is not mentioned in particular. Meanwhile, in the case where aplurality of frequency channels are used in a cell like carrieraggregation, it is possible to use a desired channel for thenotification of an FTN parameter.

Accordingly, in the present description, an example of a communicationsequence between the base station 100 and the terminal apparatus 200 inthe case where a plurality of frequency channels are used in a cell willbe described on the basis of the example illustrated in FIG. 19. FIG. 19is a diagram illustrating an example of a frequency channel used forcommunication between the base station 100 and the terminal apparatus200 in a communication system including carrier aggregation.Specifically, FIG. 19 illustrates an example of the case where the CC 0and the CC 1 are used as CCs for a transmission apparatus to transmitdata. Note that, in the case where the respective frequency channelscorresponding to the CC 0 and the CC 1 are represented as channels f0and f1, it is assumed that the magnitude relationship between thechannels f0 and f1 with respect to frequency is f0<f1. In addition, inthe example illustrated in FIG. 19, it is assumed that the CC 0 is setas a PCC, and the CC 1 is set as an SCC.

(c-1) Notification of FTN Parameter Through Channel to which FTN isApplied

First, with reference to FIGS. 20 and 21, an example of the case wherethe base station 100 uses a frequency channel to which FTN is applied tonotify the terminal apparatus 200 of an FTN parameter will be described.FIGS. 21 and 22 are explanatory diagrams each for describing an exampleof a communication sequence in the case where FTN is employed for thedownlink in the communication system in including carrier aggregation.Note that FIGS. 20 and 21 each illustrate an example of a communicationsequence between the base station 100 and the terminal apparatus 200 inthe case where the base station 100 uses a frequency channel to whichFTN is applied to notify the terminal apparatus 200 of an FTN parameter.

For example, similarly to the example described with reference to FIG.15, FIG. 20 illustrates an example of the case where FTN is employed fora downlink, and the base station 100 uses RRC connection reconfigurationto notify the terminal apparatus 200 of an FTN parameter. Note that thecommunication sequences represented by reference numerals S401 to S413in FIG. 20 are similar to the communication sequences represented byreference numerals S201 to S213 in FIG. 15, so that detailed descriptionwill be omitted. In addition, FIG. 20 illustrates an example of the casewhere FTN is applied to the channel f1 (i.e., CC 1 that is an SCC).

Specifically, in the example illustrated in FIG. 20, the base station100 uses, as represented by a reference numeral S401, the channel f1 totransmit an RRC connection reconfiguration message to the terminalapparatus 200. At this time, the base station 100 notifies the terminalapparatus 200 of an FTN parameter (e.g., compression coefficientτ_(i,p)) set for each cell.

In addition, the base station 100 performs various kinds of modulationprocessing including FTN mapping processing on transmission target dataon the basis of the FTN parameter set for each cell to generate atransmission signal. The base station 100 then uses, as represented by areference numeral S409, the channel f1 to transmit the transmissionsignal onto the PDSCH resource designated for the terminal apparatus200.

In addition, as another example, similarly to the example described withreference to FIG. 16, FIG. 21 illustrates an example of the case whereFTN is employed for a downlink, and the base station 100 uses systeminformation to notify the terminal apparatus 200 of an FTN parameter.Note that the communication sequences represented by reference numeralsS451 to S461 in FIG. 21 are similar to the communication sequencesrepresented by reference numerals S251 to S261 in FIG. 16, so thatdetailed description will be omitted. In addition, FIG. 21 illustratesan example of the case where FTN is applied to the channel f1 (i.e., CC1 that is an SCC).

Specifically, in the example illustrated in FIG. 21, the base station100 uses, as represented by a reference numeral S451, the channel f1 tobroadcast an SIB message to each terminal apparatus 200 positioned inthe cell 10. At this time, the base station 100 includes an FTNparameter in the SIB message to notify each terminal apparatus 200positioned in the cell 10 of the FTN parameter.

In addition, the base station 100 performs various kinds of modulationprocessing including FTN mapping processing on transmission target dataon the basis of the FTN parameter set for each cell to generate atransmission signal. The base station 100 then uses, as represented by areference numeral S457, the channel f1 to transmit the transmissionsignal onto the PDSCH resource designated for the terminal apparatus200.

With reference to FIGS. 20 and 21, the above describes an example of thecase where the base station 100 uses a frequency channel to which FTN isapplied to notify the terminal apparatus 200 of an FTN parameter. Notethat, although the above focuses on an example of the case where FTN isapplied to a downlink for description, it goes without saying that thesame applies to the case where FTN is applied to an uplink.

(c-2) Notification of FTN Parameter Through Predetermined Channel

Next, with reference to FIGS. 222 and 23, an example of the case wherethe base station 100 uses a predetermined frequency channel to notifythe terminal apparatus 200 of an FTN parameter will be described. FIGS.22 and 23 are explanatory diagrams each for describing an example of acommunication sequence in the case where FTN is employed for a downlinkin the communication system in which carrier aggregation is employed.Note that FIGS. 22 and 23 each illustrate an example of a communicationsequence between the base station 100 and the terminal apparatus 200 inthe case where the base station 100 uses a predetermined frequencychannel to notify the terminal apparatus 200 of an FTN parameter. Inaddition, in the present description, description will be made, focusingespecially on the case where the base station 100 uses another frequencychannel different from a frequency channel to which FTN is applied tonotify the terminal apparatus 200 of an FTN parameter.

For example, similarly to the example described with reference to FIG.15, FIG. 22 illustrates an example of the case where FTN is employed fora downlink, and the base station 100 uses RRC connection reconfigurationto notify the terminal apparatus 200 of an FTN parameter. Note that thecommunication sequences represented by reference numerals S501 to S513in FIG. 22 are similar to the communication sequences represented byreference numerals S201 to S213 in FIG. 15, so that detailed descriptionwill be omitted.

FIG. 22 illustrates an example of the case where FTN is applied to thechannel f1 (i.e., CC 1 that is an SCC), and the base station 100 usesthe channel f0 (i.e., CC 0 that is a PCC) to notify the terminalapparatus 200 of an FTN parameter. In the example illustrated in FIG.22, in the case where the base station 100 transmits or receivesinformation for controlling communication with the terminal apparatus200, the base station 100 uses the channel f0 (i.e., PCC), and in thecase where the base station 100 transmits live data, the base station100 uses the channel f1 (i.e., SCC) to which FTN is applied.

More specifically, in the example illustrated in FIG. 22, the basestation 100 uses, as represented by a reference numeral S501, thechannel f0 (i.e., PCC) to transmit an RRC connection reconfigurationmessage to the terminal apparatus 200. At this time, the base station100 notifies the terminal apparatus 200 of an FTN parameter (e.g.,compression coefficient τ_(i,p)) set for each cell.

In addition, the base station 100 performs various kinds of modulationprocessing including FTN mapping processing on transmission target dataon the basis of the FTN parameter set for each cell to generate atransmission signal. The base station 100 then uses, as represented by areference numeral S509, the channel f1 (i.e., SCC) to transmit thetransmission signal onto the PDSCH resource designated for the terminalapparatus 200.

In addition, as another example, similarly to the example described withreference to FIG. 16, FIG. 23 illustrates an example of the case whereFTN is employed for a downlink, and the base station 100 uses systeminformation to notify the terminal apparatus 200 of an FTN parameter.Note that the communication sequences represented by reference numeralsS551 to S561 in FIG. 23 are similar to the communication sequencesrepresented by reference numerals S251 to S261 in FIG. 16, so thatdetailed description will be omitted.

FIG. 23 illustrates an example of the case where FTN is applied to thechannel f1 (i.e., CC 1 that is an SCC), and the base station 100 usesthe channel f0 (i.e., CC 0 that is a PCC) to notify the terminalapparatus 200 of an FTN parameter. In the example illustrated in FIG.23, in the case where the base station 100 transmits or receivesinformation for controlling communication with the terminal apparatus200, the base station 100 uses the channel f0 (i.e., PCC), and in thecase where the base station 100 transmits live data, the base station100 uses the channel f1 (i.e., SCC) to which FTN is applied.

More specifically, in the example illustrated in FIG. 23, the basestation 100 uses, as represented by a reference numeral S551, thechannel f0 (i.e., PCC) to broadcast an SIB message to each terminalapparatus 200 positioned in the cell 10. At this time, the base station100 includes an FTN parameter in the SIB message to notify each terminalapparatus 200 positioned in the cell 10 of the FTN parameter.

In addition, the base station 100 performs various kinds of modulationprocessing including FTN mapping processing on transmission target dataon the basis of the FTN parameter set for each cell to generate atransmission signal. The base station 100 then uses, as represented by areference numeral S557, the channel f1 (i.e., SCC) to transmit thetransmission signal onto the PDSCH resource designated for the terminalapparatus 200.

As described above, the notification of an FTN parameter is issuedconcentratedly through a predetermined frequency channel, thereby makingit possible to decrease the overhead in a communication sequence thatuses another frequency channel. Note that choices of the frequencychannel used for the notification of an FTN parameter include a PCC andan SCC, but it is more desirable to employ the configuration in which aPCC is used to perform the procedure for the notification of an FTNparameter from the perspective that all the terminal apparatuses 200 ina cell are capable of the reception. In addition, as described above,applying a larger value than another CC (SCC) or 1 (τ=1) as thecompression coefficient corresponding to a PCC makes it possible to makethe procedure for the notification of an FTN parameter, or the like morestable.

With reference to FIGS. 22 and 23, the above describes an example of thecase where the base station 100 uses a frequency channel to which FTN isapplied to notify the terminal apparatus 200 of an FTN parameter. Notethat, although the above focuses on an example of the case where FTN isapplied to a downlink for description, it goes without saying that thesame applies to the case where FTN is applied to an uplink.

(c-3) Example of Case where FTN is not Applied to Physical ControlChannel

Next, with reference to FIGS. 24 and 25, an example of the case whereFTN is not applied to a physical control channel, but FTN is appliedwhen the notification of an FTN parameter is issued and data istransmitted will be described. FIGS. 24 and 25 are explanatory diagramseach for describing an example of a communication sequence in the casewhere FTN is employed for the downlink in the communication system inwhich carrier aggregation is employed. Note that FIGS. 24 and 25 eachillustrate an example of a communication sequence between the basestation 100 and the terminal apparatus 200 in the case where FTN is notapplied to a physical control channel, but FTN is applied when thenotification of an FTN parameter is issued and data is transmitted.

For example, similarly to the example described with reference to FIG.15, FIG. 24 illustrates an example of the case where FTN is employed fora downlink, and the base station 100 uses RRC connection reconfigurationto notify the terminal apparatus 200 of an FTN parameter. Note that thecommunication sequences represented by reference numerals S601 to S613in FIG. 24 are similar to the communication sequences represented byreference numerals S201 to S213 in FIG. 15, so that detailed descriptionwill be omitted.

FIG. 24 illustrates an example of the case where FTN is applied to thechannel f1 (i.e., CC 1 that is an SCC). In the example illustrated inFIG. 24, the base station 100 uses the channel f0 (i.e., PCC) totransmit and receive RRC connection reconfiguration such as a PDCCH anda PUCCH, and uses the channel f1 (i.e., SCC) to transmit and receive theother control channels (e.g., RRC connection, physical shared datachannel, and the like).

More specifically, in the example illustrated in FIG. 24, the basestation 100 uses, as represented by a reference numeral S601, thechannel f1 (i.e., SCC) to transmit an RRC connection reconfigurationmessage to the terminal apparatus 200. At this time, the base station100 notifies the terminal apparatus 200 of an FTN parameter (e.g.,compression coefficient τ_(i,p)) set for each cell (S601). In addition,the channel f1 (i.e., SCC) is also used to transmit an RRC connectionreconfiguration complete message from the terminal apparatus 200 as aresponse to the RRC connection reconfiguration message (S603).

In addition, when using a PDCCH to transmit allocation information of aPDSCH to the terminal apparatus 200, the base station 100 uses thechannel f0 (i.e., PCC) (S605).

Next, the base station 100 performs various kinds of modulationprocessing including FTN mapping processing on transmission target datato generate a transmission signal, and uses the channel f1 (i.e., SCC)to transmit the transmission signal onto a designated PDSCH resource(S609).

In addition, the terminal apparatus 200 returns an ACK or a NACK to thebase station 100 in accordance with a decoding result of the datatransmitted from the base station 100. At this time, the terminalapparatus 200 uses the channel f0 (i.e., PCC) to return an ACK or a NACKto the base station 100 (S613).

In addition, as another example, similarly to the example described withreference to FIG. 16, FIG. 25 illustrates an example of the case whereFTN is employed for a downlink, and the base station 100 uses systeminformation to notify the terminal apparatus 200 of an FTN parameter.Note that the communication sequences represented by reference numeralsS651 to S661 in FIG. 25 are similar to the communication sequencesrepresented by reference numerals S251 to S261 in FIG. 16, so thatdetailed description will be omitted.

FIG. 25 illustrates an example of the case where FTN is applied to thechannel f1 (i.e., CC 1 that is an SCC). In the example illustrated inFIG. 25, the base station 100 uses the channel f0 (i.e., PCC) totransmit and receive RRC connection reconfiguration such as a PDCCH anda PUCCH, and uses the channel f1 (i.e., SCC) to transmit and receive theother control channels (e.g., RRC connection, physical shared datachannel, and the like).

More specifically, in the example illustrated in FIG. 25, the basestation 100 uses, as represented by a reference numeral S651, thechannel f1 (i.e., SCC) to broadcast an SIB message to each terminalapparatus 200 positioned in the cell 10. At this time, the base station100 includes an FTN parameter in the SIB message to notify each terminalapparatus 200 positioned in the cell 10 of the FTN parameter.

In addition, when using a PDCCH to transmit allocation information of aPDSCH to the terminal apparatus 200, the base station 100 uses thechannel f0 (i.e., PCC) (S653).

Next, the base station 100 performs various kinds of modulationprocessing including FTN mapping processing on transmission target datato generate a transmission signal, and uses the channel f1 (i.e., SCC)to transmit the transmission signal onto a designated PDSCH resource(S657).

In addition, the terminal apparatus 200 returns an ACK or a NACK to thebase station 100 in accordance with a decoding result of the datatransmitted from the base station 100. At this time, the terminalapparatus 200 uses the channel f0 (i.e., PCC) to return an ACK or a NACKto the base station 100 (S661).

With reference to FIGS. 24 and 25, the above describes an example of thecase where FTN is not applied to a physical control channel, but FTN isapplied when the notification of an FTN parameter is issued and data istransmitted. Note that, although the above focuses on an example of thecase where FTN is applied to a downlink for description, it goes withoutsaying that the same applies to the case where FTN is applied to anuplink.

(6) FTN Control Example Based on Another Perspective Except forFrequency Channel

Next, an example of FTN control based on another perspective except fora frequency channel will be described. As described above, theimprovement of frequency use efficiency is one of the effects caused byapplying FTN. Because of such a characteristic, the effectivenessbrought about by applying FTN sometimes changes in accordance with acontrol channel of a radio resource used in a communication system.

For example, an example of the application range within which it ispossible to obtain an effect of FTN by applying FTN includes a channel(i.e., PDSCH or PUSCH). By applying FTN to a shared channel fortransmitting and receiving live data, for example, it is possible toobtain the effect of improving frequency use efficiency and throughput.

Further, in addition to a shared channel, the application of FTN to amulticast channel is included. The multicast channel is a channel and aresource used when a broadcasting data service is provided in a cellularsystem like a multimedia broadcast multicast service (MBMS) or the like.Applying FTN to a multicast channel makes it possible, for example, toexpect the improvement of the quality of the broadcasting data service.Note that the shared channel or the multicast channel corresponds to anexample of a “second control channel.”

Meanwhile, it is desirable in some cases to refrain from applying FTN toa channel used chiefly for a control system (e.g., notification ofinformation, feedback, or the like). Information of the control systemis fundamental in the establishment of communication, so that it isthought to be important to improve the reliability of transmission andreception. Therefore, it is sometimes more preferable that inter-symbolinterference be avoided by refraining from applying FTN to a channel fortransmitting or receiving information of the control system to achievestable transmission and reception of information. In addition, even inthe case where FTN is applied to a channel for transmitting or receivinginformation of the control system, it is sometimes desirable to set anFTN parameter to lessen the influence of the inter-symbol interference(e.g., a value closer to 1 is set as the compression coefficientτ_(i,p)). Note that examples of the channel of the control systeminclude a broadcast channel, a control channel, a synchronizationchannel (or a synchronization signal), and the like. Note that theabove-described channel of the control system corresponds to an exampleof a “first control channel.”

In addition, in the communication system, a reference signal forestimating fluctuations in a radio propagation path or the like issometimes transmitted besides a channel. For the purpose of maintainingthe estimation accuracy of a radio propagation path, it is sometimesmore preferable that the application of FTN to such a reference signalbe avoided or an FTN parameter be set to lessen the influence of theinter-symbol interference.

The above describes an example of FTN control based on anotherperspective except for a frequency channel.

6. Modifications

Next, a modification of an embodiment of the present disclosure will bedescribed.

<6.1. Modification 1: Example of Control of Prefix>

First, as a modification 1, an example of control of a prefix such as aCP and a pilot symbol that can function as a guard interval inaccordance with the application status of FTN such as the applicabilityof FTN or the contents of an applied FTN parameter will be described.

As described above, in FTN, regarding a signal on which FTN processinghas been performed, the signal itself contains inter-symbolinterference. Therefore, in a communication system in which FTN isemployed, even in the case where there is no delay wave in a radiopropagation path (i.e., no inter-symbol interference occurs in a radiopropagation path), measures against inter-symbol interferenceaccompanying FTN processing have to be taken in some cases. In the casewhere these are viewed from another perspective, the above-described CPcorresponds to the measures against the inter-symbol interference in aradio propagation path, so that control that adds no CP may be employedfor FTN, which contains inter-symbol interference in the first place. Inthis case, for example, in the case of the compression coefficientτ_(i,p)<1, a transmission apparatus side just has to perform control tosatisfy a CP's length N_(CP,g)=0. Such a configuration makes it possibleto further improve frequency use efficiency.

In addition, as another example, a compression coefficient may be linkedto the length of a CP. As a specific example, a transmission apparatusmay perform control such that the length N_(CP,g) of a CP decreases withdecrease in the compression coefficient τ_(i,p). Note that, at thistime, the compression coefficient τ_(i,p) does not necessarily have tobe proportional to the length N_(CP,g) of the CP. Note that, in FTN, asthe compression coefficient τ_(i,p) decreases, the influence ofinter-symbol interference increases. Therefore, as the compressioncoefficient τ_(i,p) decreases, a reception apparatus side is required totake relatively stronger measures against inter-symbol interference inaccordance with the magnitude of the influence of inter-symbolinterference accompanying the compression coefficient τ_(i,p).Accordingly, it is also possible to address the inter-symbolinterference in the radio propagation path together.

Note that the relationship between the compression coefficient τ_(i,p)and length N_(CP,g) of a CP may be managed as a control table. Forexample, Table 2 shown below demonstrates an example of a control tablein which the range of a compression coefficient and the length of a CPis associated with each other in advance. In the example shown below asTable 2, the correspondence relationship between the range of acompression coefficient and the length of a CP is managed on the basisof a compression coefficient category index. Note that the magnituderelationship between the CPs (e.g., NCP to NCP3) of the respectivecompression coefficient category indexes with respect to length shown inTable 2 is NCP0≤NCP1≤NCP2≤NCP3≤ . . . .

TABLE 2 Example of Association of Range of Compression Coefficient andLength of CP Compression Range of Coefficient Compression Category IndexCoefficient Length of CP 0 τ0 ≤ τ < τl NCP0 1 τl ≤ τ < τ2 NCP1 2 τ2 ≤ τ< τ3 NCP2 3 τ3 ≤ τ < τ4 NCP3 — — —

In addition, as another example, a specific compression coefficient andthe length of a CP may be associated with each other, and managed as acontrol table. For example, Table 3 shown below demonstrates an exampleof a control table in which the value of a compression coefficient andthe length of a CP is associated with each other in advance. Note that,in the example shown below as Table 3, it is assumed that thecorrespondence relationship between the value of a compressioncoefficient and the length of a CP is managed on the basis of acompression coefficient category index.

TABLE 3 Example of Association of Value of Compression Coefficient andLength of CP Compression Value of Coefficient Compression LengthCategory Index Coefficient of CP 0 τ0 NCP0 1 τ1 NCP1 2 τ2 NCP2 3 τ3 NCP3— — —

Note that, in the above description, the description is made, chieflyfocusing on control of the length of a CP. However, the same applies toa pilot symbol.

The above describes, as a modification 1, an example of control of aprefix such as a CP and a pilot symbol in accordance with theapplication status of FTN such as the applicability of FTN or thecontents of an applied FTN parameter.

<6.2. Modification 2: Example of Control According to Moving Speed ofApparatus>

Next, as a modification 2, an example of the case where a compressioncoefficient is controlled in accordance with the moving speed of atransmission apparatus or a reception apparatus will be described.

In the case where the moving speed of an apparatus (transmissionapparatus or reception apparatus) is high, fluctuations in a radio wavepath with respect to time also increase. Accordingly, it is anticipatedthat reception processing becomes complicated. Therefore, a transmissionapparatus side may control the value of a compression coefficient inaccordance with the moving speed of the transmission apparatus or thereception apparatus to adaptively control the load of processing on thecorresponding reception apparatus side. More specifically, thetransmission apparatus just has to perform control such that the valueof the compression coefficient increases (i.e., the compressioncoefficient has a value close to 1) with increase in the moving speed ofthe transmission apparatus or the reception apparatus. Such controlmakes it possible to perform control such that the influence of theinter-symbol interference contained in FTN itself decreases withincrease in the moving speed of the transmission apparatus or thereception apparatus.

Note that the relationship between the moving speed of an apparatus(transmission apparatus or reception apparatus) and the value of acompression coefficient may be managed as a control table. For example,Table 4 shown below demonstrates an example of a control table in whichthe moving speed of an apparatus and the length of a CP are associatedwith each other in advance. In the example shown below as Table 2, acategory referred to as mobility category is defined, and thecorrespondence relationship between the range of a compressioncoefficient and the length of a CP is associated with the mobilitycategory. Note that the magnitude relationship between the compressioncoefficients (e.g., τmobility0 to τmobility3) of the respective mobilitycategory indexes shown as Table 4 isτmobility0≤τmobility1≤τmobility2≤τmobility3≤ . . . ≤1.

TABLE 4 Example of Association of Moving Speed of Apparatus and Value ofCompression Coefficient Mobility Range of Moving Compression CategoryIndex Speed (e.g., km/h) Coefficient 0 v0 ≤ v < v1 τmobility0 1 v1 ≤ v <v2 τmobility 1 2 v2 ≤ v < v3 τmobility2 3 v3 ≤ v < v4 τmobility3 — — —

The above describes, as a modification 2, an example of the case where acompression coefficient is controlled in accordance with the movingspeed of a transmission apparatus or a reception apparatus.

7. Application Examples

The technology according to the present disclosure is applicable to avariety of products. For example, the base station 100 may beimplemented as any type of evolved node B (eNB) such as a macro eNB or asmall eNB. A small eNB may be an eNB that covers a smaller cell than amacro cell, such as a pico eNB, a micro eNB, or a home (femto) eNB.Alternatively, the base station 100 may be implemented as another typeof base station such as a node B or a base transceiver station (BTS).The base station 100 may include a main body (which is also referred toas base station apparatus) that controls radio communication, and one ormore remote radio heads (RRHs) disposed in a different place from thatof the main body. In addition, various types of terminals describedbelow may operate as the base station 100 by temporarily orsemi-permanently executing the base station function. Moreover, at leastsome of components of the base station 100 may be implemented in a basestation apparatus or a module for the base station apparatus.

In addition, the terminal apparatus 200 may be implemented as, forexample, a mobile terminal such as a smartphone, a tablet personalcomputer (PC), a notebook PC, a portable game terminal, aportable/dongle type mobile router or a digital camera, or an onboardterminal such as a car navigation apparatus. In addition, the terminalapparatus 200 may be implemented as a terminal (which is also referredto as machine type communication (MTC) terminal) that performsmachine-to-machine (M2M) communication. Further, at least somecomponents of the terminal apparatus 200 may be implemented in modules(e.g., integrated circuit modules each including one die) mounted onthese terminals.

<7.1. Application Example regarding Base Station>

First Application Example

FIG. 26 is a block diagram illustrating a first example of the schematicconfiguration of an eNB to which the technology according to the presentdisclosure can be applied. An eNB 800 includes one or more antennas 810and a base station apparatus 820. Each antenna 810 can be connected tothe base station apparatus 820 via an RF cable.

Each of the antennas 810 includes one or more antenna elements (e.g., aplurality of antenna elements included in an MIMO antenna), and is usedfor the base station apparatus 820 to transmit and receive radiosignals. The eNB 800 includes the plurality of antennas 810 asillustrated in FIG. 26. For example, the plurality of antennas 810 maybe compatible with a plurality of respective frequency bands used by theeNB 800. Note that FIG. 26 illustrates the example in which the eNB 800includes the plurality of antennas 810, but the eNB 800 may also includethe one antenna 810.

The base station apparatus 820 includes a controller 821, a memory 822,a network interface 823, and a radio communication interface 825.

The controller 821 may be, for example, a CPU or a DSP, and operates thevarious functions of a higher layer of the base station apparatus 820.For example, the controller 821 generates a data packet from data insignals processed by the radio communication interface 825, andtransfers the generated packet via the network interface 823. Thecontroller 821 may bundle data from a plurality of base band processorsto generate the bundled packet, and transfer the generated bundledpacket. In addition, the controller 821 may have logical functions ofperforming control such as radio resource control, radio bearer control,mobility management, admission control, or scheduling. In addition, thecontrol may be executed in corporation with an eNB or a core networknode in the vicinity. The memory 822 includes a RAM and a ROM, andstores a program that is executed by the controller 821, and variouskinds of control data (e.g., terminal list, transmission power data,scheduling data, and the like).

The network interface 823 is a communication interface for connectingthe base station apparatus 820 to a core network 824. The controller 821may communicate with a core network node or another eNB via the networkinterface 823. In that case, the eNB 800 may be connected to a corenetwork node or another eNB through a logical interface (e.g., S1interface or X2 interface). The network interface 823 may also be awired communication interface or a radio communication interface forradio backhaul. In the case where the network interface 823 is a radiocommunication interface, the network interface 823 may use a higherfrequency band for radio communication than a frequency band used by theradio communication interface 825.

The radio communication interface 825 supports any cellularcommunication scheme such as Long Term Evolution (LTE) or LTE-Advanced,and provides radio connection to a terminal positioned in a cell of theeNB 800 via the antenna 810. The radio communication interface 825 cantypically include a baseband (BB) processor 826, an RF circuit 827, andthe like. The BB processor 826 may perform, for example,encoding/decoding, modulating/demodulating, multiplexing/demultiplexingand the like, and executes various kinds of signal processing of layers(such as L 1, medium access control (MAC), radio link control (RLC), anda packet data convergence protocol (PDCP)). The BB processor 826 mayhave a part or all of the above-described logical functions instead ofthe controller 821. The BB processor 826 may be a memory that stores acommunication control program, or a module that includes a processor anda related circuit configured to execute the program. Updating theprogram may allow the functions of the BB processor 826 to be changed.In addition, the above-described module may be a card or a blade that isinserted into a slot of the base station apparatus 820. Alternatively,the above-described module may also be a chip that is mounted on theabove-described card or the above-described blade. Meanwhile, the RFcircuit 827 may include a mixer, a filter, an amplifier and the like,and transmits and receives radio signals via the antenna 810.

The radio communication interface 825 includes the plurality of BBprocessors 826, as illustrated in FIG. 26. For example, the plurality ofBB processors 826 may be compatible with plurality of frequency bandsused by the eNB 800. In addition, the radio communication interface 825includes the plurality of RF circuits 827, as illustrated in FIG. 26.For example, the plurality of RF circuits 827 may be compatible withrespective antenna elements. Note that FIG. 26 illustrates the examplein which the radio communication interface 825 includes the plurality ofBB processors 826 and the plurality of RF circuits 827, but the radiocommunication interface 825 may also include the one BB processor 826 orthe one RF circuit 827.

In the eNB 800 shown in FIG. 26, one or more components (thetransmission processing unit 151 and/or the notification unit 153)included in the processing unit 150 described with reference to FIG. 4may be implemented in the radio communication interface 825.Alternatively, at least some of these components may be implemented inthe controller 821. As an example, a module that includes a part (e.g.,BB processor 826) or the whole of the radio communication interface 825and/or the controller 821 may be mounted in the eNB 800, and theabove-described one or more components may be implemented in the module.In this case, the above-described module may store a program for causingthe processor to function as the above-described one or more components(i.e., program for causing the processor to execute the operations ofthe above-described one or more components) and may execute the program.As another example, the program for causing the processor to function asthe above-described one or more components may be installed in the eNB800, and the radio communication interface 825 (e.g., BB processor 826)and/or the controller 821 may execute the program. As described above,the eNB 800, the base station apparatus 820, or the above-describedmodule may be provided as an apparatus that includes the above-describedone or more components, and the program for causing the processor tofunction as the above-described one or more components may be provided.In addition, a readable recording medium having the above-describedprogram recorded thereon may be provided.

In addition, in an eNB 830 illustrated in FIG. 26, the radiocommunication unit 120 described with reference to FIG. 4 may beimplemented in the radio communication interface 825 (e.g., RF circuit827). In addition, the antenna unit 110 may be implemented in theantenna 810. In addition, the network communication unit 130 may beimplemented in the controller 821 and/or the network interface 823. Inaddition, the storage unit 140 may be implemented in the memory 822.

Second Application Example

FIG. 27 is a block diagram illustrating a second example of a schematicconfiguration of an eNB to which the technology according to the presentdisclosure can be applied. The eNB 830 includes one or more antennas840, a base station apparatus 850, and an RRH 860. Each antenna 840 maybe connected to the RRH 860 via an RF cable. In addition, the basestation apparatus 850 can be connected to the RRH 860 via a high speedline such as an optical fiber cable.

Each of the antennas 840 includes one or more antenna elements (e.g., aplurality of antenna elements included in an MIMO antenna), and is usedfor the RRH 860 to transmit and receive radio signals. The eNB 830includes the plurality of antennas 840 as illustrated in FIG. 27. Forexample, the plurality of antennas 840 may be compatible with aplurality of respective frequency bands used by the eNB 830. Note thatFIG. 27 illustrates the example in which the eNB 830 includes theplurality of antennas 840, but the eNB 830 may include the one antenna840.

The base station apparatus 850 includes a controller 851, a memory 852,a network interface 853, a radio communication interface 855, and aconnection interface 857. The controller 851, the memory 852, and thenetwork interface 853 are the same as the controller 821, the memory822, and the network interface 823 described with reference to FIG. 26.

The radio communication interface 855 supports any cellularcommunication scheme such as LTE or LTE-Advanced, and provides radiocommunication to a terminal positioned in the sector corresponding tothe RRH 860 via the RRH 860 and the antenna 840. The radio communicationinterface 855 can typically include a BB processor 856 and the like. TheBB processor 856 is similar to the BB processor 826 described withreference to FIG. 26, except that the BB processor 856 is connected tothe RF circuit 864 of the RRH 860 via the connection interface 857. Theradio communication interface 855 includes the plurality of BBprocessors 856 as illustrated in FIG. 27. For example, the plurality ofBB processors 856 may be compatible with a plurality of respectivefrequency bands used by the eNB 830. Note that FIG. 27 illustrates theexample in which the radio communication interface 855 includes theplurality of BB processors 856, but the radio communication interface855 may include the one BB processor 856.

The connection interface 857 is an interface for connecting the basestation apparatus 850 (radio communication interface 855) to the RRH860. The connection interface 857 may also be a communication module forcommunication in the above-described high speed line that connects thebase station apparatus 850 (radio communication interface 855) to theRRH 860.

The RRH 860 includes a connection interface 861 and a radiocommunication interface 863.

The connection interface 861 is an interface for connecting the RRH 860(radio communication interface 863) to the base station apparatus 850.The connection interface 861 may also be a communication module forcommunication in the above-described high speed line.

The radio communication interface 863 transmits and receives radiosignals via the antenna 840. The radio communication interface 863 maytypically include the RF circuit 864 and the like. The RF circuit 864may include a mixer, a filter, an amplifier and the like, and transmitsand receives radio signals via the antenna 840. The radio communicationinterface 863 includes the plurality of RF circuits 864 as illustratedin FIG. 27. For example, the plurality of RF circuits 864 may becompatible with a plurality of respective antenna elements. Note thatFIG. 27 illustrates the example in which the radio communicationinterface 863 includes the plurality of RF circuits 864, but the radiocommunication interface 863 may include the one RF circuit 864.

In the eNB 830 illustrated in FIG. 27, one or more components (thetransmission processing unit 151 and/or the notification unit 153)included in the processing unit 150 described with reference to FIG. 4may be implemented in the radio communication interface 855 and/or theradio communication interface 863. Alternatively, at least some of thesecomponents may be implemented in the controller 851. As an example, amodule that includes a part (e.g., BB processor 856) or the whole of theradio communication interface 855 and/or the controller 821 may bemounted in eNB 830, and the above-described one or more components maybe implemented in the module. In this case, the above-described modulemay store a program for causing the processor to function as theabove-described one or more components (i.e., a program for causing theprocessor to execute the operations of the above-described one or morecomponents) and may execute the program. As another example, the programfor causing the processor to function as the above-described one or morecomponents may be installed in the eNB 830, and the radio communicationinterface 855 (e.g., BB processor 856) and/or the controller 851 mayexecute the program. As described above, the eNB 830, the base stationapparatus 850, or the above-described module may be provided as anapparatus that includes the above-described one or more components, andthe program for causing the processor to function as the above-describedone or more components may be provided. In addition, a readablerecording medium having the above-described program recorded thereon maybe provided.

In addition, in the eNB 830 illustrated in FIG. 27, the radiocommunication unit 120 described, for example, with reference to FIG. 4may be implemented in the radio communication interface 863 (e.g., RFcircuit 864). In addition, the antenna unit 110 may be implemented inthe antenna 840. In addition, the network communication unit 130 may beimplemented in the controller 851 and/or the network interface 853. Inaddition, the storage unit 140 may be implemented in the memory 852.

<7.2. Application Example regarding Terminal Apparatus>

First Application Example

FIG. 28 is a block diagram illustrating an example of the schematicconfiguration of a smartphone 900 to which the technology of the presentdisclosure can be applied. The smartphone 900 includes a processor 901,a memory 902, a storage 903, an external connection interface 904, acamera 906, a sensor 907, a microphone 908, an input device 909, adisplay device 910, a speaker 911, a radio communication interface 912,one or more antenna switches 915, one or more antennas 916, a bus 917, abattery 918, and an auxiliary controller 919.

The processor 901 may be, for example, a CPU or a system on a chip(SoC), and controls functions of the application layer and another layerof the smartphone 900. The memory 902 includes a RAM and a ROM, andstores a program that is executed by the processor 901, and data. Thestorage 903 can include a storage medium such as a semiconductor memoryor a hard disk. The external connection interface 904 is an interfacefor connecting an external device such as a memory card or a universalserial bus (USB) device to the smartphone 900.

The camera 906 includes an image sensor such as a charge coupled device(CCD) or a complementary metal oxide semiconductor (CMOS), and generatesa captured image. The sensor 907 can include, for example, a group ofsensors such as a measurement sensor, a gyro sensor, a geomagneticsensor, and an acceleration sensor. The microphone 908 converts soundinput to the smartphone 900 to sound signals. The input device 909includes, for example, a touch sensor configured to detect touch onto ascreen of the display device 910, a keypad, a keyboard, a button, aswitch or the like, and receives an operation or an information inputfrom a user. The display device 910 includes a screen such as a liquidcrystal display (LCD) or an organic light-emitting diode (OLED) display,and displays an output image of the smartphone 900. The speaker 911converts sound signals output from the smartphone 900 to sound.

The radio communication interface 912 supports any cellularcommunication scheme such as LTE and LTE-Advanced, and executes radiocommunication. The radio communication interface 912 may typicallyinclude a BB processor 913, an RF circuit 914, and the like. The BBprocessor 913 may perform, for example, encoding/decoding,modulating/demodulating, multiplexing/demultiplexing and the like, andexecutes various kinds of signal processing for radio communication.Meanwhile, the RF circuit 914 may include a mixer, a filter, anamplifier and the like, and transmits and receives radio signals via theantenna 916. The radio communication interface 912 may also be a onechip module that has the BB processor 913 and the RF circuit 914integrated thereon. The radio communication interface 912 may includethe plurality of BB processors 913 and the plurality of RF circuits 914as illustrated in FIG. 28. Note that FIG. 28 illustrates the example inwhich the radio communication interface 912 includes the plurality of BBprocessors 913 and the plurality of RF circuits 914, but the radiocommunication interface 912 may also include the one BB processor 913 orthe one RF circuit 914.

Further, in addition to a cellular communication scheme, the radiocommunication interface 912 may support another type of radiocommunication scheme such as a short-distance radio communicationscheme, a near field communication scheme, or a radio local area network(LAN) scheme. In that case, the radio communication interface 912 mayinclude the BB processor 913 and the RF circuit 914 for each radiocommunication scheme.

Each of the antenna switches 915 switches a connection destination ofthe antenna 916 between a plurality of circuits (e.g., circuits fordifferent radio communication schemes) included in the radiocommunication interface 912.

Each of the antennas 916 includes one or more antenna elements (e.g., aplurality of antenna elements included in an MIMO antenna), and is usedfor the radio communication interface 912 to transmit and receive radiosignals. The smartphone 900 may include the plurality of antennas 916 asillustrated in FIG. 28. Note that FIG. 28 illustrates the example inwhich the smartphone 900 includes the plurality of antennas 916, but thesmartphone 900 may include the one antenna 916.

Further, the smartphone 900 may include the antenna 916 for each radiocommunication scheme. In that case, the antenna switches 915 may beomitted from the configuration of the smartphone 900.

The bus 917 connects the processor 901, the memory 902, the storage 903,the external connection interface 904, the camera 906, the sensor 907,the microphone 908, the input device 909, the display device 910, thespeaker 911, the radio communication interface 912, and the auxiliarycontroller 919 to each other. The battery 918 supplies power to therespective blocks of the smartphone 900 illustrated in FIG. 28 viafeeder lines that are partially illustrated as dashed lines in thefigure. The auxiliary controller 919 operates a minimum necessaryfunction of the smartphone 900, for example, in a sleep mode.

In the smartphone 900 illustrated in FIG. 28, one or more components(the information acquisition unit 241 and/or the communicationprocessing unit 243) included in the processing unit 240 described withreference to FIG. 5 may be implemented in the radio communicationinterface 912. Alternatively, at least some of these components may beimplemented in the processor 901 or the auxiliary controller 919. As anexample, a module that includes a part (e.g., BB processor 913) or thewhole of the radio communication interface 912, the processor 901 and/orthe auxiliary controller 919 may be mounted in the smartphone 900, andthe above-described one or more components may be implemented in themodule. In this case, the above-described module may store a program forcausing the processor to function as the above-described one or morecomponents (i.e., a program for causing the processor to execute theoperations of the above-described one or more components) and mayexecute the program. As another example, the program for causing theprocessor to function as the above-described one or more components maybe installed in the smartphone 900, and the radio communicationinterface 912 (e.g., BB processor 913), the processor 901 and/or theauxiliary controller 919 may execute the program. As described above,the smartphone 900 or the above-described module may be provided as anapparatus that includes the above-described one or more components, andthe program for causing the processor to function as the above-describedone or more components may be provided. In addition, a readablerecording medium having the above-described program recorded thereon maybe provided.

In addition, in the smartphone 900 illustrated in FIG. 28, the radiocommunication unit 220 described, for example, with reference to FIG. 5may be implemented in the radio communication interface 912 (e.g., RFcircuit 914). In addition, the antenna unit 210 may be implemented inthe antenna 916. In addition, the storage unit 230 may be implemented inthe memory 902.

Second Application Example

FIG. 29 is a block diagram illustrating an example of the schematicconfiguration of a car navigation apparatus 920 to which the technologyof the present disclosure can be applied. The car navigation apparatus920 includes a processor 921, a memory 922, a global positioning system(GPS) module 924, a sensor 925, a data interface 926, a content player927, a storage medium interface 928, an input device 929, a displaydevice 930, a speaker 931, a radio communication interface 933, one ormore antenna switches 936, one or more antennas 937, and a battery 938.

The processor 921 may be, for example, a CPU or a SoC, and controls thenavigation function and another function of the car navigation apparatus920. The memory 922 includes a RAM and a ROM, and stores a program thatis executed by the processor 921, and data.

The GPS module 924 uses GPS signals received from a GPS satellite tomeasure the position (e.g., latitude, longitude, and altitude) of thecar navigation apparatus 920. The sensor 925 may include, for example, agroup of sensors such as a gyro sensor, a geomagnetic sensor, and abarometric sensor. The data interface 926 is connected to, for example,an in-vehicle network 941 via a terminal that is not illustrated, andacquires data such as vehicle speed data generated by the vehicle side.

The content player 927 reproduces content stored in a storage medium(e.g., CD or DVD) that is inserted into the storage medium interface928. The input device 929 includes, for example, a touch sensorconfigured to detect touch onto a screen of the display device 930, abutton, a switch or the like and receives an operation or an informationinput from a user. The display device 930 includes a screen such as aLCD or an OLED display, and displays an image of the navigation functionor content that is reproduced. The speaker 931 outputs the sound of thenavigation function or the content that is reproduced.

The radio communication interface 933 supports any cellularcommunication scheme such as LTE and LTE-Advanced, and executes radiocommunication. The radio communication interface 933 may typicallyinclude a BB processor 934, an RF circuit 935, and the like. The BBprocessor 934 may perform, for example, encoding/decoding,modulating/demodulating, multiplexing/demultiplexing and the like, andexecutes various kinds of signal processing for radio communication.Meanwhile, the RF circuit 935 may include a mixer, a filter, anamplifier and the like, and transmits and receives radio signals via theantenna 937. The radio communication interface 933 may also be a onechip module that has the BB processor 934 and the RF circuit 935integrated thereon. The radio communication interface 933 may includethe plurality of BB processors 934 and the plurality of RF circuits 935as illustrated in FIG. 29. Note that FIG. 29 illustrates the example inwhich the radio communication interface 933 includes the plurality of BBprocessors 934 and the plurality of RF circuits 935, but the radiocommunication interface 933 may also include the one BB processor 934 orthe one RF circuit 935.

Further, in addition to a cellular communication scheme, the radiocommunication interface 933 may support another type of radiocommunication scheme such as a short-distance radio communicationscheme, a near field communication scheme, or a radio LAN scheme. Inthat case, the radio communication interface 933 may include the BBprocessor 934 and the RF circuit 935 for each radio communicationscheme.

Each of the antenna switches 936 switches a connection destination ofthe antenna 937 between a plurality of circuits (e.g., circuits fordifferent radio communication schemes) included in the radiocommunication interface 933.

Each of the antennas 937 includes one or more antenna elements (e.g., aplurality of antenna elements included in an MIMO antenna), and is usedfor the radio communication interface 912 to transmit and receive radiosignals. The car navigation apparatus 920 may include the plurality ofantennas 937 as illustrated in FIG. 29. Note that FIG. 29 illustrates anexample in which the car navigation apparatus 920 includes the pluralityof antennas 937, but the car navigation apparatus 920 may include theone antenna 937.

Further, the car navigation apparatus 920 may include the antenna 937for each radio communication scheme. In that case, the antenna switches936 may be omitted from the configuration of the car navigationapparatus 920.

The battery 938 supplies power to the respective blocks of the carnavigation apparatus 920 illustrated in FIG. 29 via feeder lines thatare partially illustrated as dashed lines in the figure. In addition,the battery 938 accumulates power supplied form the vehicle side.

In the car navigation apparatus 920 illustrated in FIG. 29, one or morecomponents (the information acquisition unit 241 and/or thecommunication processing unit 243) included in the processing unit 240described with reference to FIG. 5 may be implemented in the radiocommunication interface 933. Alternatively, at least some of thesecomponents may be implemented in the processor 921. As an example, amodule that includes a part (e.g., BB processor 934) or the whole of theradio communication interface 933 and/or the processor 921 may bemounted in the car navigation apparatus 920, and the above-described oneor more components may be implemented in the module. In this case, theabove-described module may store a program for causing the processor tofunction as the above-described one or more components (i.e., a programfor causing the processor to execute the operations of theabove-described one or more components) and may execute the program. Asanother example, the program for causing the processor to function asthe above-described one or more components may be installed in the carnavigation apparatus 920, and the radio communication interface 933(e.g., BB processor 934) and/or the processor 921 may execute theprogram. As described above, the car navigation apparatus 920 or theabove-described module may be provided as an apparatus that includes theabove-described one or more components, and the program for causing theprocessor to function as the above-described one or more components maybe provided. In addition, a readable recording medium having theabove-described program recorded thereon may be provided.

In addition, in the car navigation apparatus 920 illustrated in FIG. 29,the radio communication unit 220 described, for example, with referenceto FIG. 5 may be implemented in the radio communication interface 933(e.g., RF circuit 935). In addition, the antenna unit 210 may beimplemented in the antenna 937. In addition, the storage unit 230 may beimplemented in the memory 922.

In addition, the technology according to the present disclosure may alsobe implemented as an in-vehicle system (or a vehicle) 940 including oneor more blocks of the above-described car navigation apparatus 920, thein-vehicle network 941, and a vehicle module 942. That is, thein-vehicle system (or the vehicle) 940 may be provided as an apparatusthat includes the information acquisition unit 241 and/or thecommunication processing unit 243. The vehicle module 942 generatesvehicle-side data such as vehicle speed, engine speed, or troubleinformation, and outputs the generated data to the in-vehicle network941.

8. Conclusion

With reference to FIGS. 3 to 29, the above describes the apparatus andthe processing according to an embodiment of the present disclosure.

According to an embodiment of the present disclosure, for example, inthe case where focus is placed on the downlink of the communicationsystem 1, the base station 100 notifies the terminal apparatus 200 of acompression coefficient (e.g., compression coefficient decided for eachcell) decided in accordance with a communication environment as an FTNparameter. In addition, the base station 100 modulates a transmissiontarget data destined for the terminal apparatus 200, and performs FTNmapping processing on the modulated bit sequence to adjust the symbolintervals in the bit sequence. The base station 100 then transmits atransmission signal obtained by performing digital/analog conversion,radio frequency processing, and the like on the bit sequence on whichFTN mapping processing has been performed to the terminal apparatus 200.On the basis of such a configuration, the terminal apparatus 200performs FTN de-mapping processing on the bit sequence obtained from areception signal from the base station 100 on the basis of a compressioncoefficient of which the terminal apparatus 200 has been notifiedbeforehand, thereby making it possible to decode the data transmittedfrom the base station 100.

In addition, as another example, in the case where focus is placed onthe uplink of the communication system 1, the base station 100 notifiesthe terminal apparatus 200 of a compression coefficient (e.g.,compression coefficient decided for each cell) decided in accordancewith a communication environment as an FTN parameter. Upon receivingthis notification, the terminal apparatus 200 modulates transmissiontarget data destined for the base station 100, and performs FTN mappingprocessing on the modulated bit sequence to adjust the symbol intervalsin the bit sequence. The terminal apparatus 200 then transmits atransmission signal obtained by performing digital/analog conversion,radio frequency processing, and the like on the bit sequence on whichFTN mapping processing has been performed to the base station 100. Onthe basis of such a configuration, the base station 100 performs FTNde-mapping processing on the bit sequence obtained from a receptionsignal from the terminal apparatus 200 on the basis of a compressioncoefficient of which the terminal apparatus 200 has been notifiedbeforehand, thereby making it possible to decode the data transmittedfrom the base station 100.

As described above, according to an embodiment of the presentdisclosure, the communication system according to the present embodimenttakes into consideration the load of the processing of addressinginter-symbol interference in a reception apparatus, and is configured tobe capable of adaptively adjusting a compression coefficient. Such aconfiguration makes it possible to balance between the load in areception apparatus and frequency use efficiency in a more favorablemanner. That is, according to the present embodiment, it is possible touse and accommodate various kinds of frequency and various apparatusesin a communication system, and further improve the extendibility andflexibility of the communication system.

The preferred embodiment(s) of the present disclosure has/have beendescribed above with reference to the accompanying drawings, whilst thepresent disclosure is not limited to the above examples. A personskilled in the art may find various alterations and modifications withinthe scope of the appended claims, and it should be understood that theywill naturally come under the technical scope of the present disclosure.

Further, the effects described in this specification are merelyillustrative or exemplified effects, and are not limitative. That is,with or in the place of the above effects, the technology according tothe present disclosure may achieve other effects that are clear to thoseskilled in the art from the description of this specification.

Additionally, the present technology may also be configured as below.

(1)

An apparatus including:

a communication unit configured to perform radio communication; and

a control unit configured to perform control such that controlinformation for adjusting a symbol interval in a complex symbol sequenceinto which a bit sequence is converted is transmitted from thecommunication unit to a terminal, the control information being set on abasis of a predetermined condition.

(2)

The apparatus according to (1), in which

the control unit sets the control information on the basis of thepredetermined condition, and performs control such that the controlinformation is transmitted from the communication unit to a terminal.

(3)

The apparatus according to (2), in which

the control unit sets the control information such that data to betransmitted via a frequency channel having higher frequency among theplurality of frequency channels for transmitting the data to theterminal has the narrower symbol interval of the complex symbolsequence.

(4)

The apparatus according to (2) or (3), in which

the control unit allocates a radio resource to the terminal that uses aplurality of component carriers to perform communication by carrieraggregation, and sets the control information such that data to betransmitted via a component carrier of higher priority among theplurality of component carriers has the wider symbol interval of thecomplex symbol sequence.

(5)

The apparatus according to any one of (2) to (4), in which

the control unit sets the control information such that data to betransmitted via a second control channel for transmitting or receivinglive data among a first control channel for transmitting or receivinginformation for controlling communication with the terminal and thesecond control channel has the narrower symbol interval of the complexsymbol sequence.

(6)

The apparatus according to (5), in which

the control unit controls the communication with the terminal such thatthe control information for making an adjustment to shorten the symbolinterval of the complex symbol sequence is applied to only the data tobe transmitted via the second control channel among the first controlchannel and the second control channel.

(7)

The apparatus according to any one of (1) to (6), in which

the control unit performs control such that, after the controlinformation is transmitted to the terminal, data including the complexsymbol sequence the symbol interval of which is adjusted on a basis ofthe control information is transmitted from the communication unit tothe terminal.

(8)

The apparatus according to any one of (1) to (7), in which

the control unit acquires data from the terminal via the radiocommunication after the control information is transmitted to theterminal, the data including the complex symbol sequence the symbolinterval of which is adjusted on a basis of the control information.

(9)

The apparatus according to any one of (1) to (8), in which

the control information is set for each cell.

(10)

The apparatus according to any one of (1) to (9), in which

the control information is set within a range within which the symbolinterval in the complex symbol sequence does not exceed symbol length ofthe complex symbol sequence.

(11)

An apparatus including:

a communication unit configured to perform radio communication; and anacquisition unit configured to acquire control information for adjustinga symbol interval in a complex symbol sequence into which a bit sequenceis converted from a base station via the radio communication, thecontrol information being set on a basis of a predetermined condition.

(12)

The apparatus according to (11), in which

the acquisition unit acquires data from a base station via the radiocommunication after the control information is acquired, the dataincluding the complex symbol sequence the symbol interval of which isadjusted on a basis of the control information.

(13)

The apparatus according to (11) or (12), including:

a control unit configured to perform control such that data istransmitted from the communication unit to the base station, the dataincluding the complex symbol sequence the symbol interval of which isadjusted on a basis of the acquired control information.

(14)

An apparatus including:

a conversion unit configured to convert a bit sequence into a complexsymbol sequence;

an acquisition unit configured to acquire control information foradjusting a symbol interval in the complex symbol sequence, the controlinformation being set on a basis of a predetermined condition; and

a filtering processing unit configured to perform filtering processingon the complex symbol sequence, the filtering processing being based onthe control information.

(15)

The apparatus according to (14), including:

an addition processing unit configured to add a guard interval havinglength according to the control information to the complex symbolsequence, in which

the filtering processing unit performs the filtering processing on thecomplex symbol sequence to which the guard interval has been added, thefiltering processing being based on the control information.

(16)

A method including:

performing radio communication; and

performing, by a processor, control such that control information foradjusting a symbol interval in a complex symbol sequence into which abit sequence is converted is transmitted to a terminal, the controlinformation being set on a basis of a predetermined condition.

(17)

A method including:

performing radio communication; and

acquiring, by a processor, control information for adjusting a symbolinterval in a complex symbol coefficient into which a bit sequence isconverted from a base station via the radio communication, the controlinformation being set on a basis of a predetermined condition.

(18)

A method including, by a processor:

converting a bit sequence into a complex symbol sequence;

acquiring control information for adjusting a symbol interval in thecomplex symbol sequence, the control information being set on a basis ofa predetermined condition; and

performing filtering processing on the complex symbol sequence, thefiltering processing being based on the control information.

REFERENCE SIGNS LIST

-   1 system-   10 cell-   100 base station-   110 antenna unit-   120 radio communication unit-   130 network communication unit-   140 storage unit-   150 processing unit-   151 communication processing unit-   153 notification unit-   200 terminal apparatus-   210 antenna unit-   220 radio communication unit-   230 storage unit-   240 processing unit-   241 information acquisition unit-   243 communication processing unit

1. An apparatus comprising: communication circuitry configured toperform radio communication via a plurality of frequency channels; andcontrol circuitry configured to perform control such that controlinformation for adjusting a symbol interval in a complex symbolsequence, into which a bit sequence is converted, is wirelesslytransmitted to a terminal, the control information being set by thecontrol circuitry based on a predetermined condition.
 2. The apparatusaccording to claim 1, wherein the control circuitry sets the controlinformation for adjusting the symbol interval in the complex symbolsequence such that data transmitted to the terminal via a frequencychannel having a higher frequency among the plurality of frequencychannels has a narrower symbol interval than data transmitted via afrequency channel having a lower frequency among the plurality offrequency channels.
 3. The apparatus according to claim 1, wherein thecontrol circuitry sets the control information for adjusting the symbolinterval in the complex symbol sequence such that data transmitted via asecond control channel among a plurality of control channels has anarrower symbol interval than data transmitted via a first controlchannel among the plurality of control channels, and the first controlchannel and the second control channels are different types of controlchannels.
 4. The apparatus according to claim 3, wherein the secondcontrol channel is a primary control channel, and the first controlchannel is a secondary control channel.
 5. The apparatus according toclaim 1, wherein the adjusting the symbol interval in the complex symbolsequence based on the control information comprises adjusting both alength of a data part of the complex symbol sequence and a length of acyclic prefix attached to the data part of the complex symbol sequence.6. A method for performing radio communication by an apparatus via aplurality of frequency channels, the method comprising: performingcontrol such that control information for adjusting a symbol interval ina complex symbol sequence, into which a bit sequence is converted, iswirelessly transmitted to a terminal, the control information being setbased on a predetermined condition; and communicating with the terminalvia the plurality of frequency channels in accordance with the controlinformation.
 7. The method according to claim 6, wherein the adjustingthe symbol interval in the complex symbol sequence adjusting the symbolinterval such that data transmitted to the terminal via a frequencychannel having a higher frequency among the plurality of frequencychannels has a narrower symbol interval than data transmitted via afrequency channel having a lower frequency among the plurality offrequency channels.
 8. The method according to claim 6, wherein thecontrol information for adjusting the symbol interval in the complexsymbol sequence is set such that data transmitted via a second controlchannel among a plurality of control channels has a narrower symbolinterval than data transmitted via a first control channel among theplurality of control channels, and the first control channel and thesecond control channels are different types of control channels.
 9. Themethod according to claim 8, wherein the second control channel is aprimary control channel, and the first control channel is a secondarycontrol channel.
 10. The method according to claim 6, wherein theadjusting the symbol interval in the complex symbol sequence based onthe control information comprises adjusting both a length of a data partof the complex symbol sequence and a length of a cyclic prefix attachedto the data part of the complex symbol sequence.
 11. A non-transitorycomputer-readable program product containing instructions for causing acomputer to perform a method related to radio communication, the methodcomprising: performing control such that control information foradjusting a symbol interval in a complex symbol sequence, into which abit sequence is converted, is wirelessly transmitted to a terminal, thecontrol information being set based on a predetermined condition; andcommunicating with the terminal via a plurality of frequency channels inaccordance with the control information.
 12. An apparatus comprising:communication circuitry configured to perform radio communication via aplurality of frequency channels; and control circuitry configured toperform control such that control information for adjusting a symbolinterval in a complex symbol sequence, into which a bit sequence isconverted, is wirelessly received from a terminal, the controlinformation being set by the terminal based on a predeterminedcondition.
 13. The apparatus according to claim 12, wherein the controlinformation for adjusting the symbol interval in the complex symbolsequence is set such that data received from the terminal via afrequency channel having a higher frequency among the plurality offrequency channels has a narrower symbol interval than data received viaa frequency channel having a lower frequency among the plurality offrequency channels.
 14. The apparatus according to claim 12, wherein thecontrol information for adjusting the symbol interval in the complexsymbol sequence is set such that data received via a second controlchannel among a plurality of control channels has a narrower symbolinterval than data received via a first control channel among theplurality of control channels, and the first control channel and thesecond control channels are different types of control channels.
 15. Theapparatus according to claim 14, wherein the second control channel is aprimary control channel, and the first control channel is a secondarycontrol channel.
 16. The apparatus according to claim 14, wherein theadjusting the symbol interval in the complex symbol sequence based onthe control information comprises adjusting both a length of a data partof the complex symbol sequence and a length of a cyclic prefix attachedto the data part of the complex symbol sequence.
 17. A method forperforming radio communication by an apparatus via a plurality offrequency channels, the method comprising: performing control such thatcontrol information for adjusting a symbol interval in a complex symbolsequence, into which a bit sequence is converted, is wirelessly receivedfrom a terminal, the control information being set by the terminal basedon a predetermined condition; and communicating with the terminal viathe plurality of frequency channels in accordance with the controlinformation.
 18. The method according to claim 17, wherein the adjustingthe symbol interval in the complex symbol sequence adjusting the symbolinterval such that data received from the terminal via a frequencychannel having a higher frequency among the plurality of frequencychannels has a narrower symbol interval than data received via afrequency channel having a lower frequency among the plurality offrequency channels.
 19. The method according to claim 17, wherein thecontrol information for adjusting the symbol interval in the complexsymbol sequence is set such that data received via a second controlchannel among a plurality of control channels has a narrower symbolinterval than data received via a first control channel among theplurality of control channels, and the first control channel and thesecond control channels are different types of control channels.
 20. Themethod according to claim 19, wherein the second control channel is aprimary control channel, and the first control channel is a secondarycontrol channel.
 21. The method according to claim 18, wherein theadjusting the symbol interval in the complex symbol sequence based onthe control information comprises adjusting both a length of a data partof the complex symbol sequence and a length of a cyclic prefix attachedto the data part of the complex symbol sequence.
 22. A non-transitorycomputer-readable program product containing instructions for causing acomputer to perform a method related to radio communication, the methodcomprising: performing control such that control information foradjusting a symbol interval in a complex symbol sequence, into which abit sequence is converted, is wirelessly received from a terminal, thecontrol information being set by the terminal based on a predeterminedcondition; and communicating with the terminal via a plurality offrequency channels in accordance with the control information.